-- Only seconds before the bell sounded to open their World Boxing Council light heavyweight championship bout, referee Jay Nady asked Roy Jones Jr. and Antonio Tarver if they had any questions.

Tarver, unusually, said he did, and asked Jones, "Roy, what excuse are you going to use tonight?"

But Tarver didn't allow Jones -- long considered the pound-for-pound king -- any excuses, knocking him out with a thunderous left hand at 1 minute 1 second of the second round before 10,318 shocked fans at the Mandalay Bay Events Center.

It was only the second loss in 51 professional fights for Jones , who had been widely regarded as the best boxer in the world since at least 1994. And it was the only definitive defeat, as Jones's other loss came when he was disqualified in 1997 for hitting Montell Griffin when Griffin was down.

But on Saturday, a little more than seven months after Tarver (22-2) bitterly complained when Jones scored a majority decision in the same ring, Tarver backed up his boasts with the biggest punch of his career.

"I told you! I told you!" Tarver shouted at a stunned crowd, which had witnessed only the second knockdown and the first knockout of Jones's career. Tarver came into the rematch a 4-1 underdog.

Tarver won despite landing just seven punches in the 4:41 the bout took to complete.

Jones (49-2) won the first round on all three judges' scorecards, not doing much but landing the only significant punches of the round. He hit several good shots to the body, while Tarver did almost nothing.

It was more of the same in the second until the end, which came suddenly. Jones, with his back to Tarver's corner, missed a right and started to follow with a left hook. But Tarver countered with a left hook that landed square on Jones's chin.

Jones fell on his back in Tarver's corner. He rolled over, tried to get up and staggered toward the neutral corner. Nady waved off the bout as Tarver started jumping around the ring.

Jones said he had been knocked out once before, but never before in this fashion.

"I don't feel good about this," Jones said. "It was a good fight and he got me with a good shot. I tried to throw a hook and he threw the overhand and got me. . . . It can happen to the best of them."

In his exuberance, Tarver proclaimed himself the new pound-for-pound king. After the way he dismantled a man who for so long never lost fights (let alone rounds), it would be tough to argue.

Tarver and Jones, both 35, both grew up in Florida, but Tarver had to fight in Jones's shadow for years. He said he was motivated by Jones and the greatness that he achieved in winning titles at middleweight, super middleweight, light heavyweight and heavyweight.

"Roy Jones is a great fighter," Tarver said. "I want to thank him for setting the bar so high, but now it is my bar."

Boxing Note: Felix "Tito" Trinidad will come out of retirement to fight former welterweight champion Ricardo Mayorga on Oct. 2.

Trinidad hasn't fought in two years.

Trinidad retired one fight after he was stopped by Bernard Hopkins in a middleweight title unification fight in September 2001. He has said for months he planned to return to the ring, but a series of opponents fell through.

Oscar De La Hoya wanted to fight Trinidad in a rematch of the 1999 fight Trinidad won by decision, but said he couldn't get him interested. Trinidad was going to fight Shane Mosley, but then Mosley lost to Winky Wright.

Roy Jones Jr. tries to get his bearings as he gets a count from referee Jay Nady after being knocked down in the second round by Antonio Tarver in their WBC light heavyweight fight.