LAS VEGAS, (Reuters) – Bernard Hopkins won a  unanimous decision against fellow American Roy Jones Jr. in tough fight on Saturday night, finally avenging a 1993 defeat in a long-delayed re-match.

There were no knockdowns in a bout that was characterized by caution but punctuated by stoppages for accidental fouls and a near-riot in the ring at the end of the sixth round.

“It was kind of rough,” said 45-year-old Hopkins, who improved his record to 51-5-1. “Roy’s a veteran. He was tying me up. I was tying him up. It was a good fight.”

Jones, 54-7, frequently frustrated Hopkins with his effective defense but the 41-year-old rarely showed enough offense to win any of the rounds.

The pattern of each round was similar with each man feinting, Hopkins attempting to bull Jones to the ropes behind a jab and right hand and Jones looking to tie up or counter with short uppercuts inside.

“I was trying to smother him, so he couldn’t counter me,” said Hopkins. “He’s still got speed.”

The fight briefly erupted into life at the end of the sixth round. Jones spun out of a clinch in the corner and landed a short punch to the back of Hopkins’ head. Hopkins dropped to his knees and took several minutes to return to his feet.

When the round resumed, Hopkins attacked Jones with a furious flurry and the two men continued to exchange punches as the bell rang. Both corner teams and security officials entered the ring to separate the fighters and restore order.

Hopkins went down on two other occasions, from another rabbit punch and a low blow, while an accidental head butt in the 11th round opened a gash on Jones’s left eyelid.

The two men first met in the ring when they contested the vacant IBF middleweight title at RFK Stadium in Washington,  D.C., in May 1993.

Jones won a unanimous decision and then went on to add titles at super-middleweight, light-heavyweight and heavyweight.

Hopkins captured the middleweight belt in 1995 by stopping Ecuador’s Segundo Mercado and made a record 20 successful defenses of that crown until losing two close decisions to fellow American Jermain Taylor in 2005.

After Saturday’s bout, Hopkins claimed an interest in emulating Jones and challenging for a heavyweight title.

“People will think the punch in the back of my head made me a little crazy, but I want David Haye,” he said, referring to the British heavyweight who successfully defended his WBA crown against John Ruiz on Saturday.

Jones was less certain about his plans.

“I’ll go back and talk to my coaches and my dad and if we think I still have it, we’ll keep going, and if not, we’ll call it a day,” he said.