George Groves fulfilled his promise to end James DeGale's unbeaten record with a contentious majority-decision win over his bitter rival at a raucous O2 Arena on Saturday night.
The build-up to the British and Commonwealth super-middleweight title contest was dominated by spiteful bickering and goading between the unbeaten former amateur team-mates.
DeGale, the 2008 Olympic gold medalist, had vowed to avenge his defeat by Groves in the 2006 ABA championships but lightning struck twice as two judges made Groves the winner by a single point and the other had it level.
The former Dale Youth ABC team-mates had at one point seemed unlikely to meet until much further down the road, but such is the ill-feeling between them they made the fight happen sooner rather than later.
DeGale (10-0, 8KOs) came into the fight as favourite against the marginally more experienced Groves (12-0, 10KOs), largely because of the form shown in their most recent championship-level contests when DeGale stopped quality British champion Paul Smith and Groves struggled against Kenny Anderson.
A crowd of 19,000 gave Hammersmith's Groves a much warmer reception than divisive DeGale was afforded.
Harlesden's DeGale is used to being booed, though, and seemed to keep his cool in the early stages, edging a tentative opening round and finishing it with a strong one-two which was the best work of the round.
Groves improved in the second, during which DeGale was warned for use of the shoulder up close. DeGale produced perhaps the best work though as a left-right-left combination up close landed solidly.
Groves was trying to out-box the boxer and largely avoiding punishment, but was caught by a left hand early in the third and a hard right two minutes later.
Groves had a superb fourth, keeping faith with his tactics to land a right over the top and as the round wore on, two stiff right counters. DeGale landed a good right jab of his own but Groves finished strongly.
A very cagey sixth was edged by DeGale, who came out of a brief exchange better with a winged left and landed a straight left on the nose towards the round's conclusion.
For the most part it was Groves who looked quicker and sharper but when DeGale had his moments - such as a glancing but powerful left-right double at the end of the seventh - they were more eye-catching.
DeGale's promoter Frank Warren looked concerned at ringside.
In the ninth both men were cut over the left eye and DeGale took the round, finishing with a superb right jab followed by two hard southpaw lefts, arguably the fight's best action to that point.
Groves was also cut under his right eye but DeGale's was worse. The fight was hotting up as Groves took the 10th with three excellent minutes, jabbing and hammering home rights.
Groves was bloodied further in the 11th from a nasty head clash and DeGale won the round by upping his aggression and clubbing home blows.
DeGale was cut under the left eye in the final session but it was immaterial by then, the two men trading leather right to the final bell.
The excitement continued as the verdict was announced, Richie Davies calling it a 115-115 draw but Dave Parris and John Kean awarding it to Groves 115-114.
Groves was content to prove the doubters wrong and claimed he would be willing to fight DeGale again.
"Everyone was raving about him. Only two favoured me in a boxing news poll, but I have self belief," he told BBC Five Live.
"It feels good. I knew I'd won. I knew I'd done enough."
He added: "I will fight him again yeah if everything is all right and it's the right way. But now I have beaten him twice."
A disappointed DeGale disputed the judges' decision, saying: "I'm the champion. What am I to do? That's b******t."