Boxing legend Ali - who turns 70 today, only 18 days after Sir Alex did the same - was eulogised by the boss in a recent interview with Inside United. When asked which sporting event in history he'd like to have attended, he picked a world heavyweight bout on 25 February, 1964.
"Cassius Clay against Sonny Liston, I would love to have been at that. That fight earmarked the rise of the greatest athlete in the world, I think. Clay [who later changed his name to Ali] was young and brash and the build-up to the fight was fantastic.
"It was unbelievable – Clay went to Liston’s house with a bear trap, saying: “Come on, come out here, I’ve got this for you.” You could see the pure “I’m going to kill you” anger in Liston’s face. It was unbelievable theatre.
"Liston [the reigning champion] was an absolute monster but Clay knocked him out. So that fight showed for me what a great boxer he was, but also what a great personality he had.
Formerly known as Cassius Clay
Born: 17 January, 1942
Record: Won 56/61 fights
Wins by knockout: 37
"His fight against Sonny Liston earmarked the rise of the world's greatest athlete." - Sir Alex Ferguson