Muhammad Ali was defeated by five different boxers during his professional boxing career:

• Joe Frazier : The first man to beat Ali, defeating him by unanimous decision in 1971 at Madison Square Garden in what was called the "Fight of the Century"

• Ken Norton : Defeated Ali in 1973 by split decision, famously breaking Ali's jaw during the fight

• Leon Spinks : Beat Ali in 1978 by split decision in a 15-round bout in Las Vegas, handing Ali his third professional loss

• Larry Holmes : Defeated Ali in 1980 when Ali's corner stopped the fight in the 10th round; Holmes was at the peak of his career at the time

• Trevor Berbick : The last boxer to defeat Ali, winning by unanimous decision in 1981 in Ali's final professional fight

These five men are the only ones to have beaten Muhammad Ali in his 61-fight career, where he had 56 wins and 5 losses