Unbeaten George Groves overcame bitter rival James DeGale in a bloody encounter at the London 02 Arena on Saturday to add the British super middleweight title to his Commonwealth belt.

Groves, 23, took DeGale's crown courtesy of a contentious majority decision from the three judges ringside. One scored the bout 115-115, the other two 115-114 in Groves’ favor.

Often cagey, and at times pretty nasty, the much-hyped 'Grudge' showdown between the pair of warring, mouthy west London prospects had threatened to disappoint.

Groves (13-0, 10 knockouts), with David Haye’s trainer Adam Booth masterminding the tactics in his corner, got the better of the exchanges — barely –even if only due to a better work rate. By the middle rounds, however, the boos and jeering ringing out from an increasingly frustrated 18,000 crowd said everything about the fact both men were seemingly content to fight on the retreat.

Until the ninth round, that is. That's when an accidental clash of heads left both Groves and DeGale with blood streaming down their faces. Suddenly, DeGale had the motivation, so conspicuous by its absence earlier in the evening, to launch significant and sustained assaults. Suddenly, we were treated to the tear-up promised.

But for two of those scoring the fight, that spirited flurry from 2008 Olympic Gold medalist DeGale, which must have won him the final two rounds at least, had come too late in the day.

If defeated DeGale (10-1, 8KOS) was understandably seething at the outcome, Groves was positively euphoric at having finally silenced the doubters and critics.

"I've been here before, they have written me off before, but as I showed last time, this guy can't beat me. I will not let anyone beat me. I will always find a way inside of me to win," said the battered and bruised champion, whose other victory over DeGale came in the amateur ranks.

"I have always had DeGale’s number, but no disrespect to him. I have trashed talked him far too much. He's a tremendous fighter."

Promoter Frank Warren, who looks after DeGale, conceded his man had only himself to blame for the first loss of his professional career.

"James gave the fight away. He was never hurt at any stage, he looked the stronger of the two," Warren said. "I'm not taking anything away from George because he was brave and did what he had to do. But James gave it away.

"It's a bit too late to say anything to him now. But this could be a blessing in disguise. Maybe some of the backslappers will go away now and we can get down to some serious business. James is a very, very good fighter, no doubt about it. But that was his fight to win."