The Briton ended the unbeaten record of his American challenger as he made a second defence of his world title in his first fight as part of a global tournament to determine the best super-middleweight in the world over the next two years.

Froch stalked Dirrell around the ring but could not trouble his challenger until the latter rounds before he won by the judges? scores of 115-112, 115-112 to 114-113 against.

Dirrell?s breathtaking reflexes kept him out of trouble and Froch out of range, while his fast hands earned him the early rounds in a fight that lacked explosive action.

Froch extended his unbeaten record to 26 wins, while Dirrell suffered his first defeat in 19 fights.

It was also the boxers? first fight as part of the Super Six World Boxing Classic, a tournament organised by American TV broadcaster Showtime. Each boxer has three fights as part of the league format, before a semi-final and final in 2011.

Froch, 32, was backed by a sell-out 8,000 crowd in his home city while Dirrell was fighting outside of America for the first time as a professional and in his first world title fight.

But fighting away from home was not something totally alien to the challenger; Dirrell won a bronze medal at the 2004 Olympics in Athens as an amateur.

Dirrell, 27, climbed into the ring with doubts over how easily he had made the 12 stones/168 pounds weight limit. Dirrell weighed in four ounces over the limit at Friday?s weigh-in and needed a second attempt to make weight.

Dirrell?s struggle to make the weight made Froch an even bigger betting favourite than he already was before his second world title defence.

Froch?s last two fights had been thrillers: a points win over Canadian Jean Pascal and then stopping American Jermain Taylor with just 14 seconds of the last round remaining.

But this one was not so entertaining as Froch was committed to chasing Dirrell for most of the fight.

Dirrell claimed his hand speed would be Froch?s undoing and the Michigan fighter?s reflexes were sharp as well as Froch was made to miss with many shots early in the fight.

The early rounds were tense with neither boxer able to land any big shots as Dirrell switched between stances to try and confuse the champion.

Dirrell connected with a straight left in the third round but as he retreated, Froch planted a right hand on him in return.

Froch marched forward looking to strike but Dirrell glided in and out of range and it was his fast hands that saw him land the few scoring shots in rounds three, four and five.

Dirrell?s success on the counter attack becalmed the English crowd and in round five Froch was warned for wrestling his challenger to the floor out of frustration.

Froch?s knockout power is undoubted - he entered the ring having stopped 20 of his 25 opponents - but he just could not get near the elusive Dirrell until the sixth round, when he got through with a big right.

Dirrell?s composure was upset in the seventh and despite boxing neatly in the eighth, was nailed by a left hook.

But Dirrell landed the best shot of the fight in the tenth round when he landed a straight left on the counter that momentarily wobbled Froch. However, the American had been docked a point earlier in the round by the referee for holding.

Froch rallied in the latter rounds and landed some heavy blows, but then faced an anxious wait for the judges' scorecards before keeping his title by a split decision.