(written from a Production point of view)
Quark feels threatened when a con artist arrives on the station and opens up a competing bar. Meanwhile, Chief O'Brien is determined to beat Doctor Bashir at racquetball.
On the upper level of Quark's, a lady named Alsia is telling a man of her late-husband and their business, and how she saved up a little bit of latinum every year just for her retirement. But, although she says she has saved quite a tidy little sum, she doesn't think she has enough to retire on just yet, and has decided to invest the money in business. She suddenly realizes that she is divulging all her plans to a stranger, someone she has only just met, though she does say it feels like she has known him forever. As the man charms her with words, she reveals her plans to purchase a mining concession in the Vlugta asteroid belt using the spectrographic analysis data her father, a noted stellar cartographer, gained thirty years ago. She goes on to explain that, as soon as she makes his findings public, she would get seven times her investment back "overnight." Her new-found friend smiles, flattering her with compliments before suggesting the two of them form a partnership in her new endeavor. But before she can respond, Constable Odo slaps his hand on the man's shoulder and begins to frogmarch him to the security office. Alsia implores to the changeling that the two of them were only talking. "You were talking, madam. He was listening", replies Odo.
As the two of them walk along the upper level of the Promenade, Odo reveals he has been closely watching the man, whom he knows to be Martus Mazur, a refugee from the El-Aurian system. Mazur tries to trick Odo by getting him to talk about his homeworld but the Constable knows better, citing the El-Aurians' reputation for being good listeners. Mazur argues everyone needs someone to talk to and if that someone happens to require his help, he is all too happy to provide it. Odo replies he is nothing more than a con artist, a con artist that convinced an elderly couple from Pythro V to invest all of their savings into his business, a business that subsequently folded. Now they have signed a complaint against him.
As they arrive in the security office, Mazur pleads with Odo to release him, offering to talk it through with the Constable. He even offers him a drink but Odo simply laughs and activates the force field to his holding cell.
Chief O'Brien is heading down a corridor towards his newly built racquetball court, practicing some swings with his racket as he goes. As the doors swish open, he is greeted by the unexpected sight of Doctor Bashir, in full racquetball gear. The chief explains that he missed playing the game and so built the court, figuring there would be at least a couple of other players on the station, though he didn't expect Bashir to be one of them. The doctor reveals he was captain of the team at Starfleet Medical Academy, winning the sector championships in his final year much to O'Brien's surprise. Bashir continues to boast he has taken on some tough opponents, most of whom "didn't really know what they were doing". After demonstrating an ancient warm up ritual, something that makes the heart a friend to the hand, Bashir notes, he challenges O'Brien to a game using the "old style" rules, judging by his lines on the floor. The chief is noticeably annoyed with Bashir's arrogance, "I can play any style you like" he argues, before snapping at Bashir to serve. The doctor then quickly rushes to the right hand side of the court and clubs the ball at the back wall, where it bounces back, hitting the door and narrowly missing O'Brien. "One", Bashir observes.
Meanwhile, in his holding cell, Mazur is getting increasingly bothered by his cellmate's very loud snoring. After shouting at him to no avail, he nudges the man with his knee and the snoring soon stops. As the man lies there, Mazur thinks the worst and tries to wake him. At first there is no response, but with a swift grunt, he then wakes up, much to Mazur's relief. The alien named Cos, apologizes to him, explaining his health is not so good and begins to sound off his sad life story to the El-Aurian, who uncharacteristically decides to ignore him. He says he used to have everything but his life was ruined by a small device, which he takes from his pocket. Mazur's interest is suddenly piqued, believing it to be a gambling device. The man activates it and several lights begin to blink in random fashion, before rapidly dying out. He tells of how every trade deal he has struck since owning it has been a disaster, every alliance formed has fallen apart, and every endeavor has been a failure, but Mazur dismisses it as simply "rotten luck" and lies back down on his bunk. His depressed cellmate agrees that it all comes down to luck and activates it again. This time, however, the device glows a bright white, indicating a win. A big smile appears across Cos' face before he slumps back down his cell wall. He is dead, and Mazur quickly realizes it. Taking the device from his hand, he calls for a security officer, "You've got a dead prisoner in here!", he shouts.
O'Brien returns to his quarters after the racquetball match with Bashir. Keiko asks him how the training went but he can only complain about Bashir's smug attitude. "In my day", he says, "I could have wiped the court with him!" he tells Keiko. She points out that he is no longer the young man he used to be and his reflexes are bound to have gotten slower with age, though O'Brien is adamant he can beat him, it will just take some training.
In the Replimat, Bashir is telling Dax about the game and that O'Brien looked like he was going to have a heart attack at one point. Dax is surprised Bashir would allow the game to continue but the Doctor says he tried, only O'Brien wouldn't let him finish it; he even made him wait while he went off to replicate a new racket after his own had snapped. Finally, as Bashir explains, he had his nurse interrupt them with a fake emergency medical situation so he could get out of the match. Dax tells him to look on the bright side, at least he's out of the match now. But Bashir know this is only beginning; the chief wants a rematch and not only is he afraid it might injure him, but he respects the Chief's sense of pride and doesn't want to do anything that might humiliate him.
Back in the holding cell, Mazur is playing with the gambling device which he has won several times now. The device lights up yet again as Odo enters, informing him the Pythron couple is now refusing to press charges, so he can leave, much to Odo's annoyance.
In his bar, Quark is playing a game of chance with Morn, the prize being a free drink. Unfortunately, the die lands on the blue side and so Morn loses. Just then, Mazur enters and orders a drink, but with no money, Quark initially refuses him. Mazur then wagers his device on the outcome of Quark's game of chance. The die lands in his favor and so Quark pours him his drink as agreed. As he does so, he mentions that he has heard of Mazur's good fortune but, as the forty seventh Rule of Acquisition states, "never trust a man wearing a better suit than your own." Mazur demonstrates his device to Quark, which soon grabs his attention. He has a go himself, but unsurprisingly loses. He hands it back to Mazur, who proves his luck is running good today by winning again. Leaning into Quark, he offers him a proposition; with a little "tinkering" and some replication, the device could be adapted for his casino. But Quark appears uninterested. "It's just a child's toy", he says, but nevertheless places a few slips of latinum down on the prospect it could keep Nog occupied for a while. Mazur refuses the offer, demanding a hundred times what Quark had placed down, but the Ferengi isn't that keen. Mazur insists it will bring Quark profit by the end of the week, which prompts Quark to place a few more slips down. Mazur, however, still refuses, deciding to keep the device for himself. "Thanks for the drink", he says, heading out of the bar.
As he walks out onto the Promenade, Mazur sees a Bajoran woman, Roana, packing away some items from her shopfront. He approaches her and she explains that her husband recently passed away and she doesn't think she can manage the shop without him anymore. "It's so much nicer working with someone else", she recalls. Mazur then picks up a gem stone from her counter and passes it to her, "You understand.", she says.
In the racquetball court, Bashir is playing a rematch with O'Brien, but he is purposely losing the game and the chief knows it. "I don't need your charity", he remarks, "Next time, you either play your best or you don't play".
Odo is walking down the Promenade when Quark suddenly runs up to him from behind. He complains about Mazur, that he has opened a competing establishment against his exclusive contract with the station. He points to where the Bajoran woman's shop used to be. The entrance has been replaced with bright, flashing lights and Mazur is outside welcoming people in. Noticing Quark, he utters to his customers, "Welcome to Club Martus!".
Quark is following Commander Sisko on the upper level of the Promenade as he argues his point over the exclusive contract he paid considerably for, stating all gambling happens at Quark's or it doesn't happen at all. Though Sisko immediately dismisses his argument, "A few bribes to the Cardassians when they ran this station, doesn't constitute a contract. Not in the eyes of the Federation." he responds, as the two of them step into a turbolift heading down to the lower Promenade. As they exit, Quark tries a different approach, insisting Sisko owes him, that he begged for him to stay on the station when the Federation took over. Likewise, Sisko reminds him that he blackmailed, not begged him, to stay and that he can't pretend it hasn't paid off for him too. He continues to walk off down the Promenade.
As Quark shouts at him to reconsider, Rom exits the bar with Mazur, who reveals he has offered his brother a one quarter share in his establishment. Rom tells Quark that if he wants him back, he has to offer something better, but Quark simply laughs it off and lets him leave, rushing to tend to his own bar.
The customers are filling up in Club Martus, much to Mazur's pleasure. He is walking through the bar when he spots Alsia, who tells him she has gone ahead with the mining bid and the Vlugtan government has accepted it. However, they won't finalize the deal until she commissions a study on the effects of asteroid mining on intersystem navigation and she put all her money into the bid itself. Alsia tells him she needs ten thousand isiks in order to get it done and she only has a week to do it. She goes on to explain that any investor would see return of ten times that amount. Realizing the potential for profit, Mazur agrees to help her.
Rom approaches with a tray of canapés and warns him that Quark may decide to do something to the food in order to discredit his bar. After the good luck he has experienced recently, Mazur brushes it off to one side, inviting a dabo girl to sit on his lap. But as Roana enters, he quickly jumps to his feet, pretending he was disciplining her. Mazur then takes two drinks from the bar and toasts to his Roana, "the queen of the Promenade". Then proposing they "formalize" their relationship, he offers her a gift of a Bajoran earring.
In Ops, Major Kira is discussing the requirements of a new lab with Dax, who has her feet up at her console. The computer suddenly alerts them to a discovery; Dax explains she has been running a scan for a program buried in the deep code level of the database and the computer has just found it, much to her surprise. She puts it down to luck and the two of them go back to their work.
Chief O'Brien is lying in pain on the floor of the racquetball court. Bashir explains he slipped on the ball while it was in mid-air and fell on his back, to O'Brien's disbelief. Bashir tells O'Brien that he has never seen anything like it before. They are then both interrupted by the sound of one of the medical staff requesting Bashir's presence in the infirmary. The chief says they can continue their match another time but as Bashir leaves, he tells him that he didn't really enjoy as he used to and, apologizing, hopes he'll find another opponent on the station.
Disappointed, O'Brien heads for Quark's. The first thing he notices as he walks in is how empty the bar is; everyone is across the Promenade at Club Martus. In an effort to prove he can be just as much a listener as Mazur, Quark asks the chief how his game went. O'Brien begins to complain about Bashir winning all the time, but it turns out Quark isn't listening after all for he has just thought up a way to get back at Mazur.
Major Kira slams a terminal in Ops after it crashes, destroying an evaluation report she has been working on for weeks; even the backups are affected. Sisko observes he has been hearing a lot of "bad luck stories" over the past few hours, including many people who have reported to the infirmary after sustaining minor injuries. Dax jokingly tells her she has been having a great day so not to send any of it her way. Kira, however, says she thinks everyone makes their own luck right before tripping over a step on her way up to the turbolift.
In Club Martus, everyone playing the gambling device has just hit the jackpot leaving Mazur very unhappy. He reluctantly agrees to pay them all.
Meanwhile, Quark is playing with his cup and dice while concocting up a scheme. "Challenge of the galaxy", he says to himself, "Match of the century. Wonder of the wormhole. House always takes blue!"
Quark, standing on his bar, is rallying a group of customers, offering them new thrills, spills and excitement, among them is Bashir but he's confused about what Quark is referring to. The chief enters, in uniform and with his toolkit to hand, looking equally puzzled by what's going on. Quark continues his speech, introducing the "reigning champion of Starfleet, and a legend on both sides of the wormhole, Miles 'The Mechanic' O'Brien" alongside "the fast and the deadly", Julian Bashir, aka "The Doctor". Both of them are equally surprised by Quark's address, expecting to find an emergency in the bar. O'Brien shouts at Quark to get down and explain himself, but he continues with his speech, advertising "the grudge match of the galaxy" with half the winnings going to the Bajoran War Orphans Fund. He finishes by inviting his customers to place a bet on either contender while reminding them the dabo tables are open. O'Brien and Bashir are naturally outraged by Quark taking it upon himself to arrange this without their consent, but he puts the charm on and reminds them about the orphans' donation and that the monks have already made down payment on new blankets for the winter. They reluctantly give in to Quark's plan. He smiles smugly across the Promenade to Mazur, who is watching in anger.
Back in Ops, Dax is frustrated with the computer, which seems to have lost the program she was looking for. Kira arrives on the turbolift, noting that she is fine after her earlier trip, which is more than she can say for the other people in the infirmary, whose numbers are increasing. Dax hypothesizes there must be a connection between the accidents and the system failures and Sisko agrees, suggesting it may be a virus or anomaly of some sort. He sets Dax to work finding something that could affect both people and machinery in this way.
Meanwhile, thanks to Quark's scheme, Club Martus is just about empty. Rom is recounting to Mazur the times he was teased for his lobes being too small, but Mazur is too busy dwelling in his own failure and eventually snaps at Rom, before finding "comfort" in the arms of his dabo girl. At that moment, Roana walks in and witnesses his betrayal. As she still holds the lease, she orders him out of her bar and to take his devices with him, before storming out. Mazur chases after her as far as the Promenade where he sees Alsia and has another idea.
A little while later, Mazur and Alsia are in the club where he provides her with the necessary funds she asked for, approximately ten thousand isiks. He reminds her of the return she promised him; he expects ten times as much back. She promises he will get it and leaves the club. Mazur then tries his luck with one of the gambling devices but it fails on him. His luck may be coming to an end.
In his quarters, O'Brien is talking to himself in the mirror as he gets ready for the match with Bashir. Before he leaves, Keiko takes a silk handkerchief of medieval Japanese design, scented with her perfume, and ties it around his head as a good luck charm and kisses him. "Kick his butt", she roots.
Bashir is doing press-ups in the infirmary when Quark enters. He says he has brought a special gift from the Bajoran monks, a medicinal brew said to impart great energy and vigor. Bashir unscrews the bottle and takes a sniff, reeling at the smell of it. Quark tells him the monks said to drink it all in one go to get the proper effect which immediately causes the doctor to suspect he is up to something. Sure enough, after running a medical scan on the liquid, Bashir finds there is seventeen milligrams of hydroxylated quint-ethyl metacetamine, an anesthetic, which would make him hardly able to stand let alone play racquetball. Quark explains that nobody is betting on O'Brien to win so he had to do something to gain a profit from the match, and of course, raise funds for the orphans. Bashir instructs Quark that he will be paying for the orphans' blankets whatever the outcome of the match and that is the end of the discussion.
In Ops, Dax has found something. Sensors have detected strange solar neutrino activity within the station. According to the laws of probability, around half of the neutrinos should be spinning clockwise and the other half counter clockwise, yet over eighty percent of them are spinning clockwise. Dax believes it is another symptom of the unusual activity on the station.
O'Brien wishes Bashir a good game as they prepare to start. The Doctor takes the first serve, which the chief successfully counters, hitting the ball against the back wall and back to Bashir, who misses it. In Quark's everyone is watching the game on a large viewscreen as he narrates the score. O'Brien serves the next point which Bashir successfully hits back. O'Brien again successfully hits the ball back to Bashir but this time the Doctor's racket snaps in two. "Not a rousing start for the Doctor", Quark narrates.
In Club Martus, Mazur is impatiently waiting on Alsia who had promised to meet him there once she had completed the deal. Rom reminds him that one quarter of the money he loaned to her is his and he expects it back. Mazur states he only gets any profit after all expenses have been settled and since all the money has gone towards expenses, he won't getting anything. Angry with this prospect, Rom takes his jacket off and throws it at Mazur, before returning to his brother's bar with the dabo girl.
Back in the court, Bashir trips and falls to the floor in an unlucky move. O'Brien, realizing something isn't quite right, cuts the video transmission with the bar. He admits to Bashir that he is playing better than he did fifteen years ago when he played five hours a day. Bashir throws the ball straight against the back wall, expecting it to bounce back to him, but it goes to the Chief instead. Then O'Brien tries, this time ricocheting the ball around all the curves and corners of the room, though it still ends up in his hand. Something is most definitely happening. Heading for the nearest comm panel, he contacts Ops.
Sisko and Dax have come down to the racquetball court to observe the phenomenon for themselves. O'Brien says he has thrown the ball at varying angles a dozen times now and it has always ended up in his hand. Sisko links this experience to the other improbable events that have been happening on the station and Dax believes she can find out what's causing it.
They walk into Club Martus just as Mazur has lost another spin on his device. Dax notes that ninety eight percent of the neutrinos in the room are rotating clockwise and it's the machines that are causing it. Sisko asks Mazur how they shut them off but he doesn't know. He says he just told the replicator to scan the original and create copies, though he does believe they have an internal power source. With no way to turn them off, Sisko and Dax take out their phasers and shoot each of the devices, destroying them for good. Mazur claims he cannot be held responsible for what has happened and even though he would like to arrest him for it, Sisko admits he has no evidence on which to charge him. However, Odo enters and reveals he does; the elderly Pythron couple have decided to press charges after all.
Mazur is back in his holding cell when Odo brings Alsia into the room. He incorrectly assumes she has come to get him out, right before she is herself placed into a cell. Quark reveals that she just tried to scam him with "the old asteroid mining trick." He tells Mazur that he has come to let him out and takes great pleasure in the fact that he was fooled by one of his own victims. Mazur demands Quark give him two thousand isiks so he can book passage out of Deep Space 9. Quark barters with him in true Ferengi style, until the price gets lower and lower. "Go on", he says "I'm listening."
"Officer! You've got a dead prisoner in here!"
- - Martus Mazur, after his cellmate, Cos, dies
"You had a game?"
"No, he had a game. I just kinda stumbled around the court for ninety minutes and made a complete ass of myself!"
- - Keiko O'Brien and Miles O'Brien
"Sector champion, my eye. He's vulnerable to every one of my best shots. I just... I just couldn't get them there! This time."
- - Miles O'Brien
"I don't need your charity! Next time, you either play your best game or you don't play."
- - Miles O'Brien to Julian Bashir, after Bashir purposely loses a game
"I'll take a hundred times what you got here."
"Not in this space-time continuum, you won't."
- - Martus Mazur and Quark, bartering for the device
"My benevolence is known far and wide."
"Oh, it's legendary, I'm sure."
- - Quark and Martus Mazur
"Kick his butt."
- - Keiko O'Brien, to Miles before his racquetball match with Bashir
"I have a contract for which I paid considerably! All gambling on DS9 happens at Quark's or it doesn't happen!"
"A few bribes to the Cardassians when they ran this place doesn't constitute a contract. Not in the eyes of the Federation."
"He's a con artist... a crook!"
"One more won't make much difference."
"You owe me! You begged me to stay here when you first came on board, and I did. Against my better judgment."
"I didn't beg, I blackmailed you. And don't pretend it hasn't paid off for you, either."
- - Quark and Benjamin Sisko
"Where are you going?"
"Back to Quark! At least then I'll be cheated by family!"
- - Martus Mazur and Rom
Story and script
- This was one of the first episodes to be put in development for DS9's second season. (Cinefantastique, Vol. 24, No. 3/4, pp. 109-110) Jim Trombetta originally pitched the idea for this episode during season one, and the story was much different. As he later explained, "Quark gets a device that gives him a lot of good luck, at the expense of other people. Someone had dug up this machine from an ancient civilization and was using it to gamble with. And Quark started having all this good luck, while everyone else was having terrible luck and things were falling apart." (Star Trek: Deep Space Nine Companion, p. 109)
- Michael Piller decided to buy the concept and worked on it for a little while. As he explained, "It was around for a year, and Jim came up with all these quirky science fiction ideas. We had to figure ways to make them work as Star Treks. It was a little quirky for us, but you've got to take some chances." The original pitch focused on the butterfly effect, which was also the original name for the show. Martus Mazur wasn't in this version of the story; instead, he was added later by Michael Piller. Joe Menosky, who wrote the episode's teleplay, further commented, "Writers would come in and say, 'What about the chaos theory?' And someone else would say, 'Well, what about it?' Everyone would struggle but nobody would devise a story. It wasn't until Jim Trombetta pitched that Michael [Piller] saw a story." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 67; Star Trek: Deep Space Nine Companion, pp. 108-109)
- On writing the teleplay itself, Menosky further commented, "A lot of times a writer is given a six-page story that isn't in very good shape, and you look at it and think, 'What the hell am I going to do with this?' But 'Rivals' was a pleasure to work on, because Michael [Piller] had a really strong idea about what he wanted to do with Martus as a rival for Quark." (Star Trek: Deep Space Nine Companion, p. 109)
- Trombetta himself said it was extremely frustrating developing the story, "because there was this subplot of the racquetball game that they had wanted to put in a number of times and had not been able to, so they put it in this [episode] after I was gone because they felt it made the most sense since this was about games." He went on to say, "I would have liked to have done more with the quantum-luck thing. I had the idea that if randomness could be managed, then you're in a lot of trouble. Basically, the universe is random; it's a mind boggling thing. Eventually Quark would beat [Martus] by using Mr. Randomness. We never got into that, although I would have liked to." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p. 67)
- Michael Piller conceived Martus Mazur to be the wayward son of Guinan. Guinan herself was to appear in the episode but Whoopi Goldberg was unavailable. All the references to Guinan were removed and only Martus' status as an El-Aurian was retained. (Star Trek: Deep Space Nine Companion, p. 109)
- The script described Martus as "a tall, elegantly dressed and mannered man in his forties…" (Star Trek: Deep Space Nine Companion - A Series Guide and Script Library)
- Author and theoretical physicist Lawrence Krauss pointed out that neutrinos can only exist in a specific spin state, the left-handed spin state (antineutrinos are in the right-handed spin state), and therefore Dax could never have discovered a "statistically unlikely" left-handed alignment of whirling neutrinos. Science Advisor Andre Bormanis said of this error, "This was a mistake on my part; I thought neutrinos had multiple spin states like other subatomic particles, and didn't double-check. Well, as Spock noted in Star Trek II: The Wrath of Khan – nobody's perfect. (Star Trek Science Logs, p. 54) In November 2016, a group of European physicists published a paper in which they suggested the inclusion of six additional particles to the current Standard Model used to describe sub-atomic physics. Three of these would be neutrinos with a right-handed spin state.  Neutrinos with a right-handed spin state are, to current date, still unproven and only theoretical.
- Originally, there were three designs for the probability machine: the handheld device (which was initially designed larger than its appearance in the final episode), the larger device created by Martus, and a four-person gambling orb for the casino. Ultimately, only the first two designs (with some elements from the third) were incorporated into the final production. (The Making of Star Trek: Deep Space Nine, p. 47) The script described the handheld version as a "small, spherical, softball-sized, handheld GAMBLING DEVICE. It has a strange design, covered by curious angles and curves, as if fashioned from exotic seashells." 
- The racquetball court was built on the holosuite set. Due to the cost of putting up and taking down the set, it was decided not to re-use the sport. According to Siddig El Fadil (Julian Bashir), "The dartboard was cheaper, and we started using that in the third season." (Star Trek: Deep Space Nine Companion, p. 109)
- Though the racquetball scenes only took six hours to shoot, there were issues, as El Fadil later noted: "The scenes were kind of bizarre because the racquetball court was such an odd shape that the ball would bounce wrong. It was designed in a sci-fi shape, with the walls at all sorts of oblique angles, and you'd hit the ball and you wouldn't know where it would go. So we were chasing these balls around like nutters, until they finally just staged us so we could look like we were shooting the ball where we wanted it to go."
- Of the decision to have O'Brien appear shirtless, director David Livingston commented, "I thought it was important. He represents the common man on the show, and common men, when they get sweaty, take off their shirts. And so what if he doesn't look like Fabio. He looks real, like a Human being. And later on, he has this nice loving moment with Keiko, where she hands him his shirt. I fought for that." Robert Hewitt Wolfe noted, "I think it was an attempt to show he's sexy to his wife. There's some sparks between the two of them. We don't see it all the time, but it's a real ongoing thing." On the prospect of being a sex symbol, Colm Meaney (Miles O'Brien) joked, "It would seem to me that there are far more likely candidates for it!" On the idea of Bashir taking his shirt off in a future episode, El Fadil replied, "I reckoned they were going to send me to a gym for six months before they made me do a love scene." It wouldn't be until the series finale "What You Leave Behind", that Bashir gets a love scene in the form of Ezri Dax. (Star Trek: Deep Space Nine Companion, pp. 109-110)
- One of the ingredients in Quark's sedative drink is "dilithium flavoring extract oz. 435" as shown on Bashir's computer screen. This is one of the many examples of in-jokes that have been added by the show's art department throughout the series.
- The costume worn by Alexander Siddig (Julian Bashir) during the racquetball match was auctioned off in the It's A Wrap! sale and auction. The shoes are, in reality, silver-painted Nike air shoes. 
- This episode was the first to air in 1994.
- Referenced Rules of Acquisition: #47 ("Never trust a man wearing a better suit than your own") and #109 ("Dignity and an empty sack is worth the sack").
- Although by this point Guinan had not been identified as an El-Aurian, several hints are dropped in this episode, as El-Aurians are described multiple times as a "race of listeners," and Guinan referred to herself often as "a listener," and in "Evolution", referred to herself as coming from a "species of listeners." It was only in Star Trek Generations that she was confirmed to be an El-Aurian.
- Oddly, Club Martus appears to be located where the Bajoran temple normally is on the Promenade. The front of the temple had been converted to be a storefront seen in DS9: "Sanctuary". The temple was not restored until three episodes later in "Whispers".
- Cirroc Lofton (Jake Sisko) does not appear in this episode.
- Michael Piller originally had different plans for Martus's future: "When we did 'Rivals' I thought that the character of Martus had a chance of being a recurring one. It was like Harry Mudd or something like that. But I don't think it will. I thought it was an average episode, albeit with some great character stuff in it." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p.67)
- Writer Jim Trombetta wasn't entirely happy with the finished product either: "Ultimately, it seemed a little confusing. I never explained the quantum gambling device adequately. The problem is, after ten drafts there's always a problem that never quite gets solved. I've written six or seven outlines for some of these things, but then the problem gets to be part of the solution that might be plausible." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p.67)
- Ira Behr said of the episode, "I can happily say that 'Rivals' was not a show I did a lot of work on. I don't think we had a lead guest star who worked. We were looking for a Michael Caine, Dirty Rotten Scoundrels type, and Chris Sarandon was a lot more stolid and less effervescent. There were a lot of nice moments, and I loved Max [Grodenchik]. I think Rom is a great character, and he's someone we can keep exploring because the relationship between brothers is endlessly fascinating. I love the Bashir/O'Brien stuff also. I could have seen the whole just be about that. We brought the idea of random luck in a fit of needing to buy stories, which happens sometimes, but it never makes any sense. We never cared about it. It's too much to justify. I don't think there was an episode we did all year that didn't have something in it that was watchable, and this had the whole O'Brien and Bashir story, which was very watchable." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p.67)
- In contrast, director David Livingston was happy with how the episode turned out: "It was another light kind of story with kinetic elements. Working with Colm [Meaney] and [Alexander] Siddig was fun. I didn't have any time to shoot the racquetball match, so it was one of those things where you're just going on adrenaline and instinct. I was literally just shooting only the pieces that I needed. And when it was all put together, I surprised myself. It came out much better than I thought, because I had these horrible thoughts it wasn't going to work." However, he was aware that some people did not: "People just didn't like it. It was pretty much a piece of fluff, but it was fun. I had a good time doing it." (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages, p.67; Star Trek: Deep Space Nine Companion, p.108)
- One aspect of the show that did receive positive comments from fans was the racquetball sequence. Robert Hewitt Wolfe recalled, "Our e-mail fans really liked the tight suit that Bashir wore in the matches. They liked that a lot." (Star Trek: Deep Space Nine Companion, p. 108)
- Actor Armin Shimerman (Quark) believed there was opportunity for some good character rivalry scenes but in the finished episode it "didn't quite gel". Shimerman had previously worked with guest star Chris Sarandon (Martus Mazur) on Broadway fifteen years earlier but didn't feel there was the right spark in this instance: "Chris and I got along fine, but the one-upmanship that should have been there, these two swindlers trying to out swindle each other, didn't really work." (Star Trek: Deep Space Nine Companion, p. 109)
- Authors Mark Jones and Lance Parkin wrote of this episode, "A dreadful attempt at a comedy story, the sparring between Quark and his rival just doesn't work. Since that's the key to the episode, what's left is poor plotting disguised as the effects of the gambling device and a few set-pieces that couldn't even have looked that good on paper." (Beyond the Final Frontier, p. 197)
- Similarly, Star Trek author Keith R.A. DeCandido thought Chris Sarandon, "utterly fails in the role of Mazur. He’s flat, dull, uninteresting, has none of the needed spark with Armin Shimerman that the role calls for, nor do we see any evidence of the charm he’s supposed to be using on both Alsia and Roana." However, he did praise the O'Brien-Bashir racquetball rivalry, calling it, "hilarious and charming," but did say, "it’s kind of too bad that it was short-circuited by the technobabble plot, as I wanted to see how the showdown would really turn out. Still, the whole thing is wonderfully played by Colm Meaney, Siddig el-Fadil, and Rosalind Chao, and if you must watch the episode, just watch those bits." Overall, he gave this episode a "warp factor rating" of 4/10. 
Video and DVD releases
- UK VHS release (two-episode tapes, CIC Video): Volume 16, 27 June 1994
- As part of the DS9 Season 2 DVD collection
Links and references
- Rene Auberjonois as Constable Odo
- Siddig El Fadil as Doctor Julian Bashir
- Terry Farrell as Lieutenant Jadzia Dax
- Cirroc Lofton as Jake Sisko
- Colm Meaney as Chief Miles O'Brien
- Armin Shimerman as Quark
- Nana Visitor as Major Kira Nerys
- Rosalind Chao as Keiko O'Brien
- Barbara Bosson as Roana
- K Callan as Alsia
- Max Grodénchik as Rom
- Albert Henderson as Cos
Special appearance by
- Sam Alejan as Human sciences division officer
- Ivor Bartels as Human operations division officer
- Brian Demonbreun as Human sciences division officer
- Kevin Grevioux as Human operations division officer
- Sue Henley as command officer
- Randy James as Jones
- Mark Lentry as a Human command division lieutenant
- David B. Levinson as Broik
- Mary Meinel-Newport as Bolian woman
- Robin Morselli as Bajoran officer
- Tammy Rodriguez as the Yellow-skinned alien dabo girl
- Mark Allen Shepherd as Morn
- Sandra Wild as Club Martus dabo girl
- Unknown performers as
2332; 2340; 2344; 2355; 2361; 2368; 47; 5000 years ago; adopted; Alsia's father; Alsia's husband; anesthetic; appointment; ass; assistant; asteroid; asteroid mining; backhand; backup; ball; Bajor; Bajoran War Orphans Fund; Bajoran wormhole; Bashir's assistant; battle; beg; bet; bid; bidding war; blackmail; blanket; blue; Bolians; bribe; brother (sibling); butt; canapé; captain (sports); Cardassian; cargo ship; casino; champion; championship; charge; childhood; Club Martus; coin purse; complex carbohydrate; con artist/con man (crook); contract; copy; corner shot; coronary; court; dabo girl; deep code level; donation; double or nothing; drop shot; El-Aurians; El-Aurian system; emergency call; evaluation report; exercise; family; father; Federation; Final; final year; financial access code; flush; folk medicine (traditional medicine); fossil; full spectrum mineral analysis; fundraiser; gambling device; gambling machine; game; Gamzian wine; grain; hand; handkerchief; health risk; heart; heart attack; intersystem navigation; intestinal bug; invest; investor; Isiks; jackpot; Japanese; joke; Keldar; kill shot; latinum; laws of probability; lease; listener; lobe; logic; luck; marriage proposal; match fixing; "Mechanic, The" (mechanic); medical student; medicinal brew; medieval; merchant; Milky Way Galaxy; milligram; mining concession; molasses; monk; month; Naming Day; neck; nephew; Nog; Occupation of Bajor; officer; operating costs; order; orphan; overhead; Pakleds; particulate; partnership; pastime; peddle; Plygorian mammoth; poison; potassium bromide; power source; presents; Promenade; promoter; prosecco; prospecting; pulse; push-up; Pythro V; Pythrons; Pythron couple; Quark's; racquet; racquetball; recapitalization; refugee; rematch; replicator; retirement; riser shot; Roana's husband; Rules of Acquisition; Sector 001; Sector Champion; Sector Championship; security chief; security file; self-destruct; serve; scam; science; score; shaving; shop; sign; silk; snoring; solar neutrinos; space-time continuum; spatial fluctuation; spin shot; sprain; stamina; Starfleet Medical Academy; stellar cartographer; sucrose; suit; survey; sweat; symptom; synthehol; terminal; testify; throwing; time; toast; training; transmission; Top raquetball player; tournament; toy; tricorder; trust; vegetable; virus; Vlugtans; Vlugta asteroid belt; Vlugta government; Vulcan; Vulcan racquetball opponent; wall; warm-up; week; winter; year
- Substance analysis report 4611: centrose; dextrose; dilithium flavoring extract; enriched wheat flour; folic acid; hydrogenated soybean oil; hyvroxilated quint-ethyl metacetamin; niacinamide; palmitate; pyridoxine hydrochloride; substance analysis report; tribnel root extract; yeast
- "Rivals" at Memory Beta, the wiki for licensed Star Trek works
- "Rivals" at Wikipedia
- "Rivals" at StarTrek.com, the official Star Trek website
- "Rivals" at MissionLogPodcast.com, a Roddenberry Star Trek podcast
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