Ten of the heavyweight champion's greatest battles:
1: Ali third-round KO v Cleveland Williams, Houston 1966
Ali was at his devastating best against one of the hardest hitters in the sport's history.
Bouncing around the ring on the balls of his feet he married relentless and blinding speed with an unerring accuracy on his left jab. Williams barely managed to land a punch in anger.
Ali floored his opponent three times towards the end of round two and only the bell's intervention prolonged the fight into the first minute of the third, when Williams crumpled to the canvas again.
It was an amazing performance - seven minutes showcasing boxing as close to perfect as it is ever likely to get.
2: Ali 14th-round technical KO v Joe Frazier, Manila 1975
Ali triumphed in the pair's rubber match, the sheer brutality of which eclipsed even those two awesome meetings which had gone before.
Ali called it "the closest thing to death". Frazier stormed forward and swamped Ali with hooks, sustaining tremendous punishment in the process.
Frazier's trainer Eddie Futch pulled his man out at the end of the 14th round. Ali, ahead on the cards, was on the verge of quitting too.
3: Ali eighth-round KO v George Foreman, Kinshasa 1974
The Rumble in the Jungle - and the extraordinary circumstances called for Ali's most extraordinary tactics. To the disbelief of all observers Ali opted to play "rope-a-dope" with the fearsome Foreman, lolling back on the ropes and inviting punishment.
Foreman punched himself out and Ali pounced, a left and right to Foreman's head dropping the champion and winning Ali the title back.
4: Ali seventh-round KO v Sonny Liston, Miami 1964
The brooding, menacing Liston was supposed to put the loudmouth from Louisville in his place. Cassius Clay, as Ali was known then, was pronounced “scared to death” by a physician before the fight.
All the experts tipped a Liston walkover. Then Clay went out and toyed with Liston.
He made the baddest man on the planet look flat-footed, fat and old.
Liston retired on his stool at the end of the seventh and Clay - who announced his conversion to Islam after the fight - was world heavyweight champion.
5: Ali on points v Ernie Terrell, New York 1967
Ali was furious with the leading contender Terrell, who refused to refer to him by his new name in the build-up to their bout.
He made the challenger pay by inflicting upon him a sustained and deliberately drawn-out 15-round beating.
“What’s my name?” Ali repeatedly sneered during a humiliation which was as remarkable as it was unedifying.
6: Ali on points v Earnie Shavers, New York 1977
Ali was coming to the end of his career and a ferocious puncher like Shavers looked perfectly placed to take his title.
Ali was badly hurt in the second but survived and his experience and sheer courage enabled him to regroup and fashion a points lead.
By the end of the 14th Ali was exhausted - but from somewhere he summoned three more excellent minutes and even had Shavers shaking at the end.
7: Ali loses on points v Joe Frazier, New York 1971
Ali came in for some shocking punishment as he and Frazier traded vicious blows for round after round.
Ali was dropped and badly hurt in the 11th round but somehow clawed his way back to the brink of victory until Frazier decked him again in the final round to underline his superiority.
Nevertheless Ali’s star did anything but burn out in defeat.
8: Ali on points v George Chuvalo, Toronto 1966
Chuvalo was a rough, tough brawler, virtually impossible to knock out, who fancied his chances of pulling off a momentous upset and claiming the world title.
But the Ali of 1966 was an unforgiving one, an Ali on the top of his game. The champion let Chuvalo whack away to negligible effect, then smoothly did enough to take the rounds - all but one of them, to be precise.
9: Ali on points (12 rounds) v Joe Frazier, New York 1974
Bad blood simmered between the pair before their second meeting, culminating in a brawl in a television studio.
In the ring Frazier, rebounding after losing his world title to George Foreman, pushed forward as usual looking to land his devastating hooks while Ali, still on the comeback trail after dodging the draft, tried to pick him off.
Ali rocked Frazier in round two and went on to gain revenge on points.
10: Ali on points v Leon Spinks, New Orleans 1978
Spinks had shocked Ali seven months earlier to claim the title but for the rematch Ali was in better shape and the upstart new champion was ravaged by personal problems.
Ali moved better second time around and negated Spinks’ strengths to gain a clear points win and become world heavyweight champion for the third time at the age of 36.