The ninth-inning master's virtual perfection, particularly in the defining month of October, has served to underscore and magnify the imperfections of all the others plying his highly demanding trade.
From Boston to Los Angeles of Anaheim, from South Florida to Seattle, closers hear the jeers, often before they even throw their first pitch of the night.
If Rivera can retire everybody, why can't they? Why do they put runners on base, putting fans through the emotional spin cycle? Why can't they simply mow down the opposition 1-2-3 like Mo and send everybody home happy every night?
Why? Because there is only one Rivera.
Everybody else, unfortunately, is human.
To survive as a closer, a sense of proportion is essential. A sense of humor also helps. There will be bad nights, sometimes several in a row. The talk shows will be venomous. The bloggers will go bonkers. "This guy has to go. Go get another closer. Now!"
Formerly of the Rockies, Brian Fuentes of the Angels has experienced the dizzying ride in two places, in two leagues. Mile high one day, Death Valley the next. He has learned the one essential aspect of his business.
"You have to have a short memory," Fuentes said. "You can't dwell on a bad game. You have to let it go and move forward, look ahead to the next one."
Fuentes is the antithesis of the prototypical closer.
Nobody ever called him "Smoke" or "The Express." A good clocking on the radar gun doesn't go deep in the 90s. If he cracks 90, he's feeling pretty good.
He throws from the left side. There have been only a handful of successful southpaw closers. He is unconventional. He strides forward and releases from an uncommon arm slot. He has what's known as a short-arm delivery. This unorthodox style can work to his advantage or drive him a little batty if there's a tiny kink in the complicated mechanics.
"Usually when I'm having a problem, it's mechanical -- timing, release point, a small glitch that throws me off," Fuentes said. "It's just a matter of working things out. That's why I've always liked to have a lot of work. But it's something I can't control."
Despite an inconsistent workload with his team's struggles to produce late leads, Fuentes has been on a roll with 18 of his past 19 outings scoreless, shaving his ERA from 6.23 to 3.22.
"He's been terrific," Angels manager Mike Scioscia said. "Brian's throwing the ball at a high level right now. We'd love to get him in more save situations. We need our offense to support our pitching."
No member of a baseball team is more dependent on his teammates' success than the closer. Fuentes had 55 save opportunities last season and nailed down 48, leading the Majors. That team finished 97-65.
Hovering around .500 all season, the current Angels have provided Fuentes with few opportunities to maintain a consistent groove. He struggled early and heard the boos, most assuredly, in his home ballpark.
"You have to tune that out," he said. "Nobody wants to be booed, but you have a job to do. You can't dwell on things like that."
Having nailed down 17 of his past 18 save chances, he is 23 for 27. His 71 saves over the past two seasons lead the Majors. Next? That man Rivera, with 66.
Left-handed hitters are batting .114 against him. His .197 overall batting average against is tied for ninth in the American League.
While the man from Merced, Calif., is getting it done, his words suggest he's not fully satisfied.
"I don't feel like I've been real smooth," he said recently. "I've had some traffic, but I'm getting the job done. I don't really look at the numbers, but I know they've been good.
"There were some stretches [of inactivity] last year, five or six days. But I've never had to deal with it this much. This year has been consistently inconsistent. Every year is a learning process. This year, I'm just riding it out."
He is riding out a two-year, $17.5 million contract with a $9 million option for 2011 that vests if he finishes 55 games this season. That seems out of reach, but agreement on a new contract with the Angels could keep him out of free agency.
On the other hand, his value could be high, given the demand for proven closers.
"I focus on today, what's in front of me," Fuentes said. "That's always been my attitude. There's nothing to be gained from speculating about those things. We have a lot of season left. If I pitch the way I can, those things will work themselves out."
There is no swagger in his walk. He doesn't pace or stomp around the mound and make crazed faces at hitters. He's no Al Hrabosky. Nobody's ever going to call him a madman.
Everyman. That's Brian Fuentes. There's nothing pretentious or out of the ordinary about the guy. He could be working at the local post office, for all his neighbors would know.
"Brian's a great role model for the younger guys," setup man Kevin Jepsen said. "He's so even keel. He doesn't get too high or too down. He's a pro. I've learned a lot being around guys like Brian, Darren Oliver, Scot Shields. Every game is important, but you have to keep things in perspective."
There's only one Mariano Rivera.
But that doesn't mean every other closer should be a target of boos and talk show venom, simply because they don't retire every hitter they face.
Lyle Spencer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.