As Mariano Rivera prepares to retire, the closer's farewell tour has become a central subplot to the season. Major League Baseball's all-time saves leader has been greeted warmly in each of his road stops, and the Yankees are planning a ceremony of their own to honor Rivera's illustrious career in September.

Rivera will be the last active player to regularly wear uniform No. 42, with the number having been retired throughout MLB in 1997 to honor the achievements of barrier-breaking great Jackie Robinson. During his 19-year big league career, Rivera has also chiseled his own mark on the number's legacy. In honor of Rivera and his contributions, MLB.com is commemorating 42 notable moments from Rivera's career -- the 42 Days of Mo.

It's always referred to as "The Aaron Boone Game."

In Game 7 of the 2003 American League Championship Series, Red Sox manager Grady Little may have left Pedro Martinez in too long, sending him out to start the eighth inning. The Yankees finally got to him for three runs, tying the score at 5-5 and eventually pushing the game into extra innings.

The next big moment comes in the bottom of the 11th inning. Nobody out. Boone steps up and launches the first pitch he sees out of the park for a walk-off homer.

Yankees win. They're off to the World Series.

But how'd they get to that point? How'd they hold an offense led by Nomar Garciaparra, Manny Ramirez and David Ortiz scoreless for the three final innings?

Mariano Rivera.

"He's why we won this game," catcher Jorge Posada said afterward. "He's why we won this series."

Rivera had already pitched five innings over three games in the series. But the season's fate was on the line, and the pitcher who manager Joe Torre wanted on the mound in that moment was Rivera.

"The way he steps it up in the playoffs, it's almost not fair," Yankees teammate Jason Giambi said after Game 7. "He's cartoon-like. Going out for a third inning, he would have gone out there for a fourth. He wasn't going to lose this game."

It took Rivera 48 pitches, 33 of which were strikes, to hold the Red Sox scoreless on two hits over the three innings.

After Boone homered to win the game, he said, "I just didn't want [Rivera] to have to pitch too long tonight."

It was the first time Rivera had pitched three innings in a game since 1996. And since then, he's done it just once, in May 2006.

Whatever it took, Rivera was going to pitch the Yankees into the 2003 World Series. Two years after losing Game 7 of the 2001 World Series against the D-backs, Rivera was named the ALCS Most Valuable Player.

Less than three months earlier, Rivera caused concern in New York by blowing four saves in six opportunities. The blip didn't last long, though.

"He's been completely amazing since everybody thought he lost it," Yankees starter Mike Mussina said. "Everybody said, 'This guy can't pitch.' There was a part of the season when people thought he'd never get anybody out again, that his run as closer was done. All of a sudden he turned it right up again."