Mayweather, who hung up his gloves in 2017, made the statement in an interview. He said, "Ken Norton really beat Ali all three times, go back and look at the fights."
The five-weight world champion has never been shy about praising himself. He's even called himself 'The Best Ever'. Mayweather's career saw him defeat greats like Manny Pacquiao, Oscar De La Hoya, and Canelo Alvarez.
Ali and Norton fought three times. Their first bout in March 1973 ended with Norton winning by split decision. Ali evened the score in September 1973, also by split decision. Their final meeting in September 1976 was a close battle. Ali won by unanimous decision, but some fans felt it could have gone either way. Norton called the result a 'robbery'.
There's a story that Ali told George Foreman he didn't think he could beat Norton before their last fight. This adds weight to Mayweather's claim.
Ali, known as 'The Greatest', left a huge mark on boxing. He was involved in epic clashes such as the 'Rumble In The Jungle' against George Foreman and the 'Thrilla In Manila' against Joe Frazier.
Mayweather's comments have sparked debate among boxing fans. They're now looking back at those Ali-Norton fights with fresh eyes.