From 'Thrilla' to 'Rope-a-Dope': The top five fights that created a legend
Ali v George Foreman - Thanks to the vision of a new promoter called Don King, the fight was set for Kinshasa in what was then known as Zaire, whose despotic president Mobutu Sese Seko stumped up the cash in a bid for international recognition.
Even an enforced one-month delay due to a cut eye for Foreman did nothing to quench Ali's enthusiasm, and by the time the pair stepped in the ring in October 1974, Ali was ready.
His rope-a-dope strategy of absorbing punishment was genius and eighth-round KO stunning.
Cassius Clay v Sonny Liston
The 22-year-old was prepared to risk it all against the ogreish champion Liston, who was coming off the back of two consecutive first-round victories over Floyd Patterson.
At the end of the fourth round, Clay returned to his corner claiming to be blinded by a substance on Liston's gloves - he was ready to pull out, but his vision slowly returned through round five, and by the sixth he was back to his best.
After his most dominant round yet, Clay noticed Liston spit out his gum shield and quit on his stool. Clay jumped to his feet in jubilation.
Ali v Leon Spinks II
Just when it seemed Ali's brutal win over Frazier in October 1975 had taken most of the fight out of him, he returned to record a triumph which deserves to rank alongside his very best.
At the age of 36, no longer quite so fleet of foot and teetering in terms of punch resistance, Ali somehow willed himself to rise once more and become the first man in history to win the world heavyweight title three times.
Spinks had embarrassed Ali in their first fight but he won the rematch in stunning style.
Ali v Cleveland Williams
He may have had other fights that earned more column inches but many maintain the true boxing greatness of Ali was never better exemplified than the night in November 1966 when he took on the ageing but ferociously hard-hitting Williams at the Houston Astrodome.
The crowd - an indoor record of 35,460 - sensed an upset, and Williams certainly came equipped. A big puncher, he had made his name in two brutal bouts against Liston in 1960, both of which he lost. He was, however, out-classed by Ali's stunning speed and power in a masterclass.
Muhammad Ali v Joe Frazier
Frazier swarmed all over Ali, slamming home enormous left hooks and setting a brutal pace for what was a savage fight in Manila.
The pace was unrelenting through 14 rounds, with both fighters dealing and sustaining tremendous punishment, before Frazier's trainer Eddie Futch decided to pull his man out before the start of the final round.
Unbeknown to Futch and Frazier at the time, Ali was also considering quitting, reportedly urging his corner to cut off his gloves, and later describing the bout as "the closest thing to death" he had ever known.