George Foreman has paid tribute to old rival Muhammad Ali, saying he "is bigger than boxing" and the toughest man he ever fought.
The three-time world heavyweight champion, who suffered with Parkinson's disease for 32 years, died aged 74 in Phoenix, Arizona after being admitted to hospital on Monday night with a respiratory condition.
Ali and Foreman met in one of the sport's most iconic bouts - the Rumble in the Jungle on October 30, 1974 in Zaire, where 32-year-old Ali reclaimed the world heavyweight title after seven years of waiting.
Foreman had dismantled both Joe Frazier and Ken Norton before his meeting with Ali and was heavy favourite going into the fight, unleashing an onslaught in the early rounds as the challenger retreated to the ropes.
However, Ali sensed his opponent had punched himself out and delivered a stunning knockout in the eighth round to regain the crown he had not held since being banned from boxing in 1967 for refusing to fight in the Vietnam War.
The two became friends in the aftermath of the bout and Foreman said his old rival was in a class of his own.
"No better word to describe Muhammad Ali - the greatest," Foreman told Fox News.
"You got into the ring with him and you expected to beat up a guy, beat up a fighter of which I'd beaten everybody, but this time I had gotten into the ring with this phenomenon and there was no way he was going to lose.
"And that's the way he felt about life, no way he was going to lose. He was the greatest. I had never been into the ring with anyone tougher in my life.
"To say he was the best fighter would be a put-down to Muhammad Ali - he is bigger than boxing. For us to talk about him as a boxer is a put-down. The man was something special.
"In Africa, Japan, Europe, everywhere, the name was 'Ali! Ali!' and I got so tired of that but they loved him. The whole world loved this man but it wasn't about boxing, they didn't care if he won or lost, they loved him."