Diego Corrales

On January 20, 2001, Corrales challenged Ring No. 2 ranked Super Featherweight and #7 Pound-For-Pound Floyd Mayweather Jr. for the WBC super featherweight title and recorded his first knockdown and first loss. In the bout, Mayweather knocked down Corrales five times (three times in the seventh round and twice in the tenth). After the fifth knockdown, Corrales' corner stopped the fight, despite Corrales' protests.

Shortly after the Mayweather fight, Corrales served 14 months in prison after opting for a plea bargain on charges he faced for abusing his pregnant wife, Maria.[8]

In 2003, Corrales returned to the ring. After easily winning four fights, Corrales fought against Ring No. 1 ranked Super Featherweight Joel Casamayor. After the sixth round, the fight was stopped because of a deep cut inside of Corrales' mouth. On March 6, 2004, there was a rematch for the vacant WBO super featherweight title. Corrales won by close split decision.

On August 7, 2004, Corrales fought former two-time Super Featherweight champion and current WBO Lightweight champion, Acelino Freitas, who came into the bout unbeaten. Corrales won the fight, via TKO in the tenth round, making Corrales a two weight champion. Freitas won the early rounds, but by the later rounds he was visibly tired and began to be caught by Corrales. After rising from his third knockdown, Freitas walked away from the referee and quit.

On May 7, 2005, Corrales defeated WBC and Ring Lightweight champion José Luis Castillo via TKO in the tenth round, giving Corrales his fourth title in 2 weight classes. The fight is almost universally regarded as the best fight of 2005.[9][10][11] Both men stood in front of each other, battering each other with hard combinations and power punches throughout the entire fight. Finally, in the tenth round, Castillo knocked Corrales down. Seconds later, Castillo knocked Corrales down again. Corrales managed to beat the count, and, after a point was taken away for excessive spitting out of the mouthpiece, Corrales connected with a punch that Castillo later called "a perfect right hand."[12] Corrales then trapped Castillo against the ropes and landed numerous punches, causing the referee, Tony Weeks, to stop the fight.

A rematch between Corrales and Castillo occurred on October 8, 2005. On the day before the fight, Castillo weighed-in 3½ lb over the 135 lb (61 kg) lightweight limit. Since Castillo did not make the weight, the fight became a non-title bout. The two fighters continued with the same fighting style that they had used in the first fight, trading inside punches throughout the first three rounds. Early in the fourth round, Castillo knocked down Corrales with a left hook to his chin. Corrales wobbled to his feet at the referee's count of ten, causing the fight to end.

Corrales vs. Castillo III, dubbed "The War to Settle the Score," had been scheduled for February 4, 2006, but it was postponed because of a rib injury that Corrales suffered while training. The fight was rescheduled for June 3, 2006. At the weigh-in, however, Corrales weighed the 135 lb (61 kg) lightweight limit whereas Castillo weighed 139½ lb—causing the fight to be cancelled. Corrales later sued Castillo for punitive damages.

Corrales was scheduled to defend his lightweight title in a third bout against Joel Casamayor on October 7, 2006. However, Corrales weighed in 5 pounds over the limit. He was given two hours to shed five pounds, but came back at 139 pounds. Corrales would have been stripped of the title if he had won the bout, but Casamayor defeated him by split decision for the WBC and The Ring lightweight titles.

On April 7, 2007, fighting in the welterweight division, Corrales lost a unanimous decision to Joshua Clottey.[13] Corrales was dropped in rounds 9 and 10 and lost by the scores of 97–90, 98–89 and 100–87.