James Toney stopped Evander Holyfield in the ninth round in Las Vegas to possibly signal the end of the former world champion's career.
The technical knock-out came with one minute and 18 seconds to go in the ninth round of the non-title fight.
Although Holyfield made a confident start, Toney soon proved he was going to be a difficult opponent.
The IBF cruiserweight title holder caused Holyfield all sorts of problems in the fourth round with some powerful right hooks and body shots and he continued to dominate after that.
Holyfield fought bravely, but his reflexes weren't what they used to be -
and he missed often with wild left hooks.
Holyfield was bleeding from the mouth from the middle rounds on and was taking a beating from straight right hands that Toney seemed to land at will.
In the ninth round, Toney rained punches on Holyfield which sent him to the canvas and his corner called an end to the fight.
"Holyfield is a great fighter, a real warrior who came to fight, but he never hurt me once - I'm indestructible," said Toney after the victory.
"I'm ready to fight anybody out there, any time, anywhere. I'll knock them all over. My talent speaks for itself."
Holyfield, who won only two of his previous seven fights, had vowed to fight until he became the undisputed heavyweight champion again and he refused to call it a day after the defeat.
"He was just too quick for me. Even the times I got in position to go
forward, he had the agility to get away," said Holyfield.
"He just kept getting his punches off before me, he kept getting into
position before me and he just outmanoeuvred me.
"Of course I'll now go home and evaluate where I stand, and when you don't do well the first thought is always to quit.
"That's what everybody does when they have a bad performance.
"But to make a decision now would be an emotional decision."