Levallois, France:David Haye knocked out Jean-Marc Mormeck in the seventh round Saturday to take the Frenchman's WBC-WBA cruiserweight titles.
The British fighter was floored in the fourth round and fought defensively as Mormeck tried to finish the contest.
Instead, Haye caught Mormeck with a big uppercut in the seventh and followed it with a right hook that put his opponent on the canvas.
Mormeck got to his feet just before the count of 10, but the referee ruled it a technical knockout.
"I was up against one of the best cruiserweights of all time," Haye said. "I knew I had to be in beautiful shape for this fight. He really hurt me in the fourth round, he hit me in the temple and my legs went, it was a great shot."
Haye improved to 20-1 overall, with 19 knockouts. Mormeck lost for the fourth time in 37 contests.
The first round was even and Mormeck edged the second round and caught the Briton with a big left hook.
Haye responded with heavy body shots in the third, but Mormeck dominated the fourth and put Haye down with another left hook, and the Briton got up on the count of eight.
"I got him with a left (hook) but could not follow it up," Mormeck said. "He had a lot of mobility which bothered me, he moves well on the ropes. I could not really develop my boxing, I was always one step behind."
In the fifth round, Mormeck was caught with an uppercut, but he responded with a heavy right hand that rocked Haye back. Haye used his reach to peg Mormeck back in the sixth.
Mormeck, who is promoted by Don King, had won back his belts from O'Neil Bell in March with a unanimous points decision after losing them to the Jamaican in January 2006.
The 35-year-old said he is not considering retiring.
"I will rest, analyze and see what mistakes I made," Mormeck said.