Former world heavyweight champion Mike Tyson said he will quit boxing after losing to Irish journeyman Kevin McBride in Washington on Saturday.
Tyson looked far from comfortable during his fight which many expected him to win, and referee Joe Cortez stopped the fight before round seven.
McBride, from Monaghan, was awarded the bout on a technical knockout.
"I'm not going to fight again. I haven't got the fighting guts or the heart any more," said the 38-year-old.
Tyson, who has a record of 50 wins, including 44 knockouts, six defeats and two no-contests, said he did not want to disgrace the sport.
"I was just fighting to pay off the bills," he added. "I'm not an animal anymore."
Referee Cortez halted the bout after a manic sixth round.
Tyson was penalised two points for a head-butt that opened a cut under McBride's left eye.
McBride then had Tyson against the ropes and pushed him to the canvas, where he remained until after the bell rang.
Tyson returned to his stool only for trainer Jeff Fenech to signal to the referee that his boxer would be unable to continue.
Two judges had Tyson leading 57-55 after six rounds while the third had the 32-year-old McBride ahead by the same margin.
"He's a tough warrior," the 32-year-old McBride said of Tyson.
"He's perhaps one of the greatest warriors of all time. I just got him at the right time."
McBride picked up just £80,000 for beating Tyson, who received £2.75m.
"I don't know if it's the end of the road for Mike Tyson, but it sure is the start of the road for me," said McBride.
"This win was for the pride of Ireland. I proved everyone wrong."