Roy Jones Jr., the WBC and WBA light heavyweight champion, claimed the IBF portion of the title tonight with a brutal beating of Reggie Johnson in which he won every round.

Jones punished the Houston fighter from the third round on, punching him at will in the late rounds. "Any time somebody comes to beat me, that's what I do," Jones said.

Each judge scored it 120-106. Jones (40-1, 33 knockouts) became the first undisputed light heavyweight champion since Michael Spinks relinquished the title in 1985 to campaign as a heavyweight.

"It didn't mean much to me. I already knew I was the best fighter in the world," said Jones, who dominated despite a rib injury during training.

Jones, 174 pounds, used a straight right 1 minute 58 seconds into the first round to knock down Johnson. The IBF champion got up quickly, but was bleeding from his right eye. In the third round, Jones countered a right from Johnson with a left-right combination that sent Johnson (39-6-1) to the canvas. Again Johnson got up quickly and the bell ended the round. By that time, blood was streaming from Johnson's eye.

Johnson, 171, was only able to fight back in spurts by the fourth round. The rest of the time he was backing away or covering up. When he managed to get inside, Jones punished him with jabs and uppercuts.

"I'm going in there with caution," Johnson said, "because the punch that gets you is the one you don't see. He does a lot of things wrong, but his hand speed makes up for it. He's got fantastically fast hands."

By the fifth round, Jones was hitting Johnson at will.

At one point, he backed Johnson to the ropes, looked at Michael Jordan seated in the front row and shouted, `Watch this!" before throwing a flurry of jabs.