Hopkins first secured the belt in 2001 when he knocked out Felix Trinidad before making 20 successful title defences, becoming the oldest world champion when he beat Jean Pascal at 46 years of age in May last year.
But the younger, faster Dawson finally brought an end to Hopkins’s reign with judges Steve Weisfeld and Richard Flaherty each had it 117-111 while Luiz Rivera scored the fight at 114-114, a score that left fans and commentators bemused.
"I did what I came to do," Dawson said. "I got my belts back."
The build-up to the fight was filled with hype after their first bout in Los Angeles last November ended in controversy when Dawson scored a TKO in the second round only to be stripped of the win when he was found to have deliberately fouled Hopkins, throwing him to the canvas out of a clinch and injuring the older American’s shoulder.
But the re-match in Atlantic City was a scrappy affair with neither fighter managing to land more than a couple of punches at a time. Dawson nearly put a series of punches together once or twice but the most significant damage Hopkins could do was with his head.
An head-butt in the fourth round was the worst of the two Hopkins landed, Dawson needing attention from cutman Rafael Garcia to close a wound on his left cheek.
"I kept my composure," Dawson said. "Bernard fought his heart out, but I'm the younger guy, so I had to be the aggressor. I kept my composure even with all the head-butts.
“My head is hurting from all of the head-butts. But I've got to give him credit. He's a future Hall of Famer. He's a helluva fighter, but he is a dirty fighter. If you can get through 12 rounds with him, you can get through anything.”
The biggest flurry of action came in the fifth round when Hopkins connected with a punch and nearly sent off-balance Dawson to the canvas. Dawson recovered, however, before Hopkins tripped into the ropes just before the bell rang.
The only other highlight of an otherwise poor fight came in the 11th when Hopkins tackled Dawson and both fighters went crashing to the canvas.
But once again both men got back up to finish the fight, a loss that could signal the end of the 47-year-old Hopkins’s career.