6 fights that have defined Floyd Mayweather Jr.

He's down to what he says will be the last five fights of a remarkable career, which means Floyd Mayweather Jr. still has a few pay-per-views to sell before it's over.

First up will be Saturday night, when Canelo Alvarez is given the best chance of beating Mayweather any fighter has had since Oscar De La Hoya dropped a close decision six years ago. It's a fight that Mayweather hopes will erase any talk of him picking opponents, and one that could go a long way toward cementing his legacy in the sport.

''If I have chosen 44 opponents at the right time, then I had the right team,''' Mayweather said. ''It means I was smart with my career.''

He's 36 now and has been fighting professionally for 17 years. Forty four times he has entered the ring, and 44 times his hand was raised at the end of the fight. Alvarez is undefeated, too, winning all 42 of his fights, though not against nearly the caliber of opposition Mayweather has faced.

Here's a look at six fights that have defined Mayweather's career:

MAYWEATHER-TODOROV: Officially this goes into the books as Mayweather's last loss, though it would be hard to find anyone outside Bulgaria who thought Serafim Todorov won his 125-pound semifinal against Mayweather in the 1996 Olympics in Atlanta. Even the referee thought Mayweather won, raising his arm instinctively as the 10-9 decision in favor of the Bulgarian two-time world champion was announced. Mayweather didn't help his own cause by not throwing a punch in the final 15 seconds, and had to settle for the bronze medal. It was a mistake he would not repeat as a pro. ''They say he was the world champion,'' Mayweather said. ''Well, we know who the real champion is.''

MAYWEATHER-HERNANDEZ: Mayweather had only had 17 pro fights when he went up against Genaro Hernandez for a piece of the 130-pound title, and some in boxing thought he was rushing things against the once-beaten champion. But Mayweather was fast and he was slick and Hernandez took a lot of punishment before his corner mercifully stopped the fight after eight rounds. Mayweather, who was paid $137,000 for the Oct. 3, 1998 bout, would reach into his own pocket and pay for funeral expenses for Hernandez when he died of cancer in 2011 at age 45.

MAYWEATHER-CORRALES: This Jan. 20, 2001 clash of two unbeaten fighters showed just how much Mayweather had separated himself from others in just a short time in his pro career. Mayweather was also finding his voice, vowing before the bout that he would beat Diego Corrales - who was facing jail time for beating his pregnant wife - ''just like he beat that woman.'' Mayweather gave Corrales a beating, knocking him down five times, with the corner of Corrales finally throwing in the towel after the final knockdown in the 10th round. ''Believe me, this guy is something special,'' former heavyweight champion and HBO commentator George Foreman said.

MAYWEATHER-GATTI: This June 25, 2005 fight was the first pay-per-view for Mayweather, and he showed a knack for promoting by calling Arturo Gatti a club fighter who didn't deserve to be in the ring with him. A sellout crowd at Atlantic City's Boardwalk Hall thought otherwise, booing Mayweather when he entered the arena held aloft on a throne by four men dressed as Roman gladiators. Mayweather quickly quieted the crowd that had come to see their hometown hero, landing hard counter punches from the opening bell and easily evading the wild punches thrown by Gatti. It was a total mismatch, with the end finally coming after the sixth round when Gatti's corner stopped its fighter from taking further punishment.

MAYWEATHER-DE LA HOYA: The fight that was supposed to save boxing was the richest ever, thanks to a record 2.5 million pay-per-view buys. More important, it launched HBO's ''24/7''' series that gave viewers an inside look at both boxers. De La Hoya played his part as the Golden Boy and Mayweather played his even better as the bad guy who argued with his father, rapped with 50 Cent and spent long periods counting piles of $100 bills. The May 5, 2007 fight itself wasn't a classic and De La Hoya had the early edge by using his jab effectively, but Mayweather began finding his range and landing solid punches in the later rounds to pull off a narrow win. The fight was the blueprint for future Mayweather promotions, with the boxer trading on his bad guy image to make his bouts must-see TV.

MAYWEATHER-COTTO: There was a feeling in boxing that Mayweather had to get more offensive minded if he was to continue to be a big draw, and he was in this May 5, 2012 fight against one of the sport's harder punchers in Miguel Cotto. Mayweather paid the price, getting hit with some good punches early and looking afterward like he had taken a beating. Again, though, Mayweather solved the style of his opponent in the 154-pound fight, and using both speed and power, dominated in the later rounds en route to a unanimous decision. ''You're the toughest guy I ever fought,'' Mayweather told Cotto afterward.