Russian Sergey Kovalev retained his trio of light heavyweight world titles by stopping former champion Jean Pascal in the eighth round in Montreal.
The 31-year-old is now unbeaten in 27 bouts, 24 wins coming by knockout.
Pascal, 32, who won the World Boxing Council belt in 2009 and defended it three times, suffered the first knock-down of his career in the third round.
The Canadian was pinned to the ropes in the eighth, when all three judges had the score 68-64 for Kovalev.
American-based Kovalev remains World Boxing Association, World Boxing Organization and International Boxing Federation champion.
He had captured two of those belts last November with a unanimous 12-round decision over former middleweight world champion Bernard Hopkins, the first time he been taken past the eighth round.
Haitian-born Canadian Pascal landed some punishing blows in the fourth and fifth rounds and called for a rematch after only the third defeat of his career, insisting: "I was still in the fight."
Kovalev was down himself in the eighth round, in what was ruled a slip, before two hard rights to Pascal's head prompted Puerto Rican referee Luis Pabon to end the contest.