Unbeaten light-heavyweight world champion Artur Beterbiev defeated Britain's Anthony Yarde to retain his WBC, IBF and WBO belts.
Beterbiev won in eight thrilling rounds at London's Wembley Arena on Saturday.
The 38-year-old sent the Briton to the canvas with a lethal right and, after a count, the challenger's corner asked the referee to stop the fight two minutes and one second into the round.
Montreal-based Beterbiev, 38, was behind on two of the three judges' scorecards before the knockout blow, took his professional record to 19-0-0.
Yarde, 31, is now on 23 wins with three defeats and no draws.
"He gave one of the best fighters in the world the toughest fight he's ever had," said promoter George Warren of Yarde.
"I had him up (on the scorecard). It was a pendulum fight almost, it swung like a pendulum. Anthony started really well. He showed that he can hurt him and keep him off him and at bay."
Beterbiev also hoped that his future bout with Russia's unbeaten WBA champion Dmitry Bivol for the undisputed title might happen.
"I want Bivol," he said. "This right now is everything. In this fight we have four belts, it's a really good fight I think."
Yarde was an underdog going into the fight but his stock is likely to rise after an impressive display.