James DeGale became world champion by beating Andre Dirrell on points in their IBF super-middleweight title clash in Boston.
Harlesden’s 2008 Olympic gold medallist floored the highly regarded American twice in the second round, with a thunderous overhand left doing the damage.
Dirrell recovered and gave DeGale plenty of problems, but a late flurry from the Londoner saw him win a unanimous decision and make history by becoming the first British boxer to win Olympic gold and a professional world title.
He faced a talented opponent in Dirrell, whose only previous defeat was a split points decision against Carl Froch in 2009 – a fight many observers believed the man from Michigan had won.
But DeGale, 29, grasped his opportunity to secure the vacant title that was up for grabs after Froch opted to relinquish the belt.
And he paved the way for a potential rematch with arch rival and fellow West Londoner George Groves, who won a close points decision when the pair met in May 2011 – DeGale’s only loss.
Groves, twice beaten by Froch having been knocked out in their rematch last year after being controversially stopped while ahead in their first encounter, is in line for another world title shot.
Hammersmith’s former British, European and Commonwealth champion is expected to challenge WBC champion Badou Jack later this year and a victory could lead to a unification showdown with DeGale.
Dirrell did well to make it past the second round after being sent to the canvas by a vicious shot.
The 32-year-old touched down again as DeGale followed up but he made it to the end of the round and appeared to have the upper hand in some of the subsequent rounds, although they seemed tough to score.
Canadian judge Alan Davis had the bout 117-109 in DeGale’s favour, which seemed somewhat bizarre, while Daniel Fitzgerald of the United States and Britain’s Howard Foster both scored it 114-112.