LAS VEGAS, Nevada, (AFP) - American Bernard Hopkins connected with a left hook to the body to knock out compatriot Oscar de la Hoya in the ninth round and retain the undisputed world middleweight title.
Hopkins, the World Boxing Association, World Boxing Council and International Boxing Federation champion, made a record 19th successful defence of the title and even picked up De la Hoya's lightly regarded World Boxing Organization belt.
He became the first fighter to knock out De la Hoya, connecting with the left just under De la Hoya's ribcage in the middle of the ninth.
De la Hoya went down with a groan and couldn't respond before referee Kenny Bayless completed the 10-count.
"I set him up with a jab, and then I threw the left," Hopkins said. "Then I heard the 'uh' sound, and I knew the wind was completely out of him."
"He got me right on the button," De la Hoya said. "I tried getting up, but I couldn't do it. I couldn't breathe."
The knock-out, at 1min 38sec of the round, lifted Hopkins' record to 45-2-1 with 32 wins inside the distance.
De la Hoya, who has held titles at 135, 140, 147 and 154 pounds before moving up this year to the 160-pound middleweight ranks, fell to 37-4.
At the time of the knockout, judges Dave Moretti had Hopkins ahead 79-73. Paul Smith made it 78-74 for Hopkins, while Keith McDonald had De la Hoya leading 77-75.
Hopkins, who said before the fight he expected to have to chase De la Hoya, admitted he was surprised in the early rounds by De la Hoya's willingness to take him on.
"He didn't run, I give him a lot of credit," Hopkins said. "He came to box. The struggle was trying to get him to do what I wanted to do - that was hard in the first few rounds."
But as the fight progressed, the bigger, more powerful Hopkins inexorably took control.
De la Hoya, whose only previous outing in the middleweight ranks was an unimpressive 12-round decision over Felix Sturm in June, said he couldn't fault his performance, and the small cut he suffered on the palm of his left hand and had stitched on Wednesday wasn't a factor.
"I felt fine, everything was perfect," De la Hoya said. "I'm proud of my performance. I'm very proud of what I tried to accomplish.
"He's the middleweight champion of the world," De la Hoya said. "What can I say?"
De la Hoya, by virtue of his proven drawing power, was to take home 30 million dollars, while Hopkins was to make at least 10 million - the bigget pay-day of his career.
On the undercard, Juan Manuel Marquez retained his World Boxing Association and International Boxing Federation featherweight titles with a unanimous, if lackluster, 12-round decision over fellow Mexican Orlando Salido.
Marquez improved to 43-2-1 and stayed on track for a rematch with Manny Pacquiao. The two fought to a draw on May 8. Two of the judges made it 117-111 for Marquez, while the third gave it to him 118-110. Salido fell to 23-9.