The former world champion had a very controversial win against Jose Luis Castillo in 2002.
Why the result was questioned is because Castillo looked the more dominant boxer out of the two.
It was pretty evident towards the final rounds, to most people that is anyway, that the Mexican was winning the fight and Mayweather was frustrated.
Castillo came into the bout with a 9lb weight advantage over Mayweather, which was probably one of the reasons why the American was struggling in the latter stages.
At the end of round nine, Castillo took a strong left-handed jab to the face from his opponent unexpectedly, as the bell had already been rung to signal the end of the round.
TV judge Harold Lederman was disappointed with Mayweather’s performance in the last few rounds.
Ultimately, he judged the fight 115-111 in Castillo’s favour.
But winning by unanimous decision, the officials decided ‘Pretty Boy’ Floyd was the new lightweight champion of the world.
Boos were heard amongst the crowd after the decision.
Legendary HBO boxing commentator Jim Lampley said this after the decision: “Not the fight we saw. Definitely not the fight that this announce team was watching at ringside.
“Not the first time it’s happened.”
The final statistics of the fight backed up Lampley’s statements.
Castillo had landed 203 punches to Mayweather’s 157, with a 40% landing rate to 35%.
The Mexican also landed 107 more power punches than his opponent, and still landed at a higher rate.
In Mayweather’s post-fight interview, he was quick to blame his injured left arm when asked if it was a tough fight.
“I beat this guy with a messed-up arm, my arm is messed-up.
“But I don’t have no excuse, I don’t ever back down or turn off fights.”
When asked again if it was a tougher fight than he anticipated, he responded: “With one arm yes, if he wants a rematch, we can do it again.”
On December 7, 2002, Mayweather silenced his critics with a convincing win over Castillo in their rematch.