ATLANTIC CITY. Devon Alexander made the first successful defence of his IBF welterweight title against Lee Purdy at Boardwalk Hall in Atlantic City.Had Alexander lost the fight, Purdy would not have claimed his belt as the Colchester fighter failed to make weight for a bout he accepted at four weeks’ notice.However under the rules the American’s victory goes down a defence of the title he won from Randall Bailey last October.Alexander was a class above Purdy throughout, landing slick right hooks and uppercuts from start to finish while the Englishman, staying close to his man with a heavy guard at all times, was only able to land the occasional decent shot.Purdy’s close friend and ranking middleweight boxer Darren Barker, running a corner for the first time, made the decision to withdraw his fighter before the start of the eighth round, much to the chagrin of ‘Lights Out’.Purdy nonetheless showed his toughness against a top competitor at short notice, while Alexander said after the fight he is now targeting a big bout, against someone such as Floyd Mayweather or Amir Khan, after cruising to victory despite hurting his left hand in round two.