A legendary career was built on such temperament, which is what allows Rivera to maintain his composure as he is surrounded by sharks as he weaves in a boat.
Or by Boston Red Sox as he teeters on the mound.
"Well, it was interesting," Rivera said by way of getting into his ninth-inning adventure on the precipice of the Yankees' season.
A 2-0 lead was halved, the bases were loaded, no one was out and, as Mike Mussina evaluated from the dugout, "He was missing by a foot on balls he usually misses by an inch -- stuff you don't usually see when Mo is pitching."
Then, just like flipping a switch, the familiar Mo returned to strike out Coco Crisp, get Jason Varitek on a weak infield pop, strike out Julio Lugo and pull Captain Jack back up from the side of the cliff.
What? Well, the Yankees' escape in a game they absolutely had to have unfolded like a scene from "Pirates of the Caribbean," where Johnny Depp's character falls off the cliff but, on the way down, grabs a protruding branch.
"Mo has that great quality of creating a mess and then cleaning it up," said New York third baseman Alex Rodriguez. "He's amazing. Even in the worst spots, he just looks confident."
Leave it to the Red Sox and the Yankees to turn ordinary into extraordinary.
The only thing special about the first 165 of the 178 minutes of Saturday afternoon action in Yankee Stadium was Mussina, who had answered the Yankees' siren call of desperation with brilliance.
When Jose Veras and Kyle Farnsworth followed Mussina's six zeroes with one each of their own, New York's agony appeared certain to come to a formulaic end.
When their starter hands off a seventh-inning lead to the bullpen, the Yankees are a remarkable 37-1. This means they have virtually perfected that Holy Grail of modern baseball: Shortening the game for a well-defined, and flawless, relief shuttle.
Except, this time the only thing Rivera shortened was everyone's breath.
A 2-0 lead looked like Fort Knox with Rivera guarding it. This was his first save opportunity in a week, but he had yet to allow a single run while racking up his first 22 saves.
That stretch of unique perfection was quickly marred. J.D. Drew singled, Manny Ramirez was a hit-by-pitch target for the third time and Mike Lowell drilled an RBI single.
Then Rivera also bounced a pitch off Kevin Youkilis' wallet, loading the bases. Rivera is no peacenik, but within eight pitches, he had matched the numbers of batters he had hit in his prior 56 appearances.
This was weird.
"But you always just have the feeling that Mo will get out of it," Rodriguez said.
"You can't have doubts," Rivera said a little later, far from the madding crowd and the shaking stands. "You have to make pitches, and if you have doubts, a lot of things can happen.
"What I tell myself is, 'Whatever happened [has] happened already. Now you have to make your pitches and get out of it.'"
He needed only 11 pitches to do that.
Crisp was dismissed on three straight.
Varitek swiped at a 2-0 pitch to his liking, but could lift it only as far as first baseman Wilson Betemit.
"He's Mariano Rivera. But in that situation, I got myself out," Varitek said. "[The pitch] was probably up just enough where I just cut through it. I still wanted to stay aggressive there. I didn't get it done."
Lugo cut through a 1-2 cutter. Now it was done.
It was only one small step forward for New York, which had fallen nine games off Tampa Bay's pace with 7-0 and 6-4 losses in the first two of this four-game series. But a backwards step would have been far bigger.
"We needed that," Rodriguez nodded. "It was a big game for us to win."
The only difference between the Yankees who'd tested manager Joe Girardi's patience for a week and Saturday's was Mussina, by blanking the Red Sox through six on four hits for his eventual 11th win.
The Yankees themselves mustered only six hits off rookie right-hander Justin Masterson, who was Justin Masterful, and three relievers. Which has been their quota for seven of the past eight games (around that 18-7 hiccup against Texas), in which they have now totaled 39 hits and 13 runs.
"We scored enough runs to find a way to win," Mussina said. "Hopefully we'll find another way to win Sunday."
Mussina found a way to muffle a team that had already raked him twice this season, two losses in which the Red Sox piled 15 hits and nine runs on him in 8 2/3 innings.
But that was nearly three months ago, which is an eternity in Moose years.
"I'm not the same person I was in those games," Mussina said. "Being 100 percent free of injury has allowed me to make adjustments -- which you always have to do, or they'll find someone else to do the job.
"Being healthy is allowing me to throw the ball to the other side of the plate, to throw the breaking ball in fastball counts. ... I've changed every
"Well," Mussina corrected after a brief pause, "I still throw right-handed."
Saturday he did. Next time out, Thursday in Pittsburgh, who knows? You can, obviously, teach an old Moose new tricks.