AMIR Khan today expressed his disappointment at not being chosen by Floyd Mayweather for what the latter says will be the last fight of his career.

Mayweather last night announced he will face Andre Berto on September 12 in Las Vegas.

Bolton superstar Khan is one of a few welterweights who had been hoping for a shot at the unbeaten pound-for-pound king.

Khan's name has long been linked as a possible challenger to Mayweather whereas Berto is something of a surprise choice.

And it will not go unnoticed that Berto is a stablemate of Khan's and has the same trainer in Virgil Hunter.

Mayweather has long insisted his last fight would be in September when his current six-fight deal with Showtime expires, with Khan insisting at several points that a deal was close for a showdown between him and the American veteran.

Mayweather, aged 38, currently holds the WBA and WBC titles at 147 pounds and his his fight with Berto will be his 49th.

Khan said in a statement today: “I’m disappointed not to have got the fight for what is the third time after having been one of the frontrunners.

"However, there are many big fights out there for me and I’m going to continue working hard to establish myself at the top of the welterweight division.

"Floyd Mayweather has fought the biggest names throughout his career and has earned the right to face whoever he chooses.

"I wish my stablemate Andre Berto and trainer Virgil Hunter the very best of luck in the fight.

"I have seen how hard Andre trains and works and know that he is ready to give Floyd a very tough night.”

Mayweather was last in the ring on May 2 when he overcame Manny Pacquiao in the most lucrative fight in the history of boxing and, while there was talk of a rematch, the Filipino has since undergone shoulder surgery that could rule him out for up to a year.

American Berto, who will be 32 when the pair meet, was undefeated in his first 27 fights but has suffered three losses in his last six – one to a man who had been defeated 10 times – to take his record to 33-3.

Khan said at the start of June: "I don't think I have ever been closer to getting the fight with Floyd Mayweather than I am at this moment.

"The indications are that I have strengthened my case with my win over (Chris) Algieri and I believe there is every chance the fight could be confirmed within the next two weeks."

That never emerged as Mayweather adopted a risk-free approach to what he claims will be his final outing against a man rated a 16/1 underdog against the 1/100 favourite.

Only one more win is needed for Mayweather to equal Rocky Marciano's fabled record of 49-0.

Khan was heading a queue of worthy opponents hopeful of meeting the world's highest-grossing sportsman.

Danny Garcia and Keith Thurman were equally viable alternatives.