Andre Ward outclassed and outmuscled Nottingham's Carl Froch to win the Super Six super-middleweight tournament in Atlantic City.
American Ward was too quick and too slick for his British rival, landing at will with razor sharp jabs and hooks and even bullying Froch at times.
Ward, who added Froch's WBC belt to the WBA belt he already owned, was the winner on all three judges' scorecards.
"I couldn't really get anything going, he was too slippery," said Froch.
"I wanted to put my shots together but he moves low and slips and slides, he's very clever up close.
"It was very frustrating for me tonight. Fair play to him."
Ward, meanwhile, felt his superior speed was the key to his victory.
"I was surprised at how slow Froch was. We were able to beat him to the punch," said Ward, an Olympic champion in 2004.
"You don't get points for leaving the chin open. You can't fight like that and expect not to get hit."
Oakland native Ward is now unbeaten in 25 fights and can now claim to be one of the top few pound-for-pound fighters on the planet after a technically dazzling display.
He may choose to fight Canada's IBF champion Lucian Bute next, although bigger matches await at light-heavyweight, where veteran Bernard Hopkins is among the title-holders.
The 34-year-old Froch, meanwhile, falls to 29 wins and two defeats and it is unclear where his career goes from here.
He may choose to fight Denmark's Mikkel Kessler, who beat him in the early stages of the Super Six tournament in 2010, or indeed Bute.
However, a more intriguing possibility is a match-up against Welshman Nathan Cleverly, the WBO title-holder at light-heavyweight.
Ward, 27, had the better of a cagey opening round, landing with a snap hook and some sharp jabs as the Englishman, a notoriously slow starter, struggled to get to grips with his speed.
Round two was more of the same as Ward, refusing to yield the centre of the ring, continued to outfox his opponent, although Froch did come on strong in the closing seconds.
Froch had some success to the body in round three but Ward, landing with a couple of right hands over his opponent's low-slung left hand, still took the session.
Ward peppered Froch with left hooks in round four and while Froch attempted to draw the American into a brawl, Ward, as he said he would, matched him for strength on the inside.
Froch wore a clubbing left hook at the start of the fifth but worked his way back into proceedings as Ward backed off in the closing stages of the round.
However, Ward stepped it up again in the sixth, waiting for Froch to fire, striking on the counter and rattling Froch with a couple of stinging hooks just before the bell.
At the halfway stage it was already evident that Froch might need a knockout but it was Ward who continued to press the action in round seven, even getting the better of the close exchanges.
Referee Steve Smoger was an almost invisible presence in the ring as both men went at it, although he did have a word with Froch when he landed with a shot after the bell at the end of the eighth.
If that was a sign of frustration, Froch even showed signs of dejection in the ninth, looking to his corner as Ward continued to outspeed and outmuscle him.
In an effort to lift their man, Froch's corner told him Ward was tiring before round 10, but this was wishful thinking as Froch's increasingly ragged defence continued to be breached by coruscating shots.
Ward did show signs of fatigue in the final two rounds but he had already done more than enough to win the fight.
John Keane's card seemed to be the most accurate, the English judge scoring it 118-110 to Ward, while John Stewart and Craig Metcalfe scored it 115-113.
Froch hinted he would be keen on a rematch, saying he felt he could beat Ward "on a good night".
"I'll speak to my promoter [Eddie Hearn] and have a look at what options are out there," he said.
"I honestly feel I could beat Andre Ward. I'd have to work on some technical things, but there are other fights out there."
Froch's defeat means British boxers have now lost 10 world title fights out of 12 in 2011, leaving Cleverly as the country's sole world champion.