Amir Khan insisted he could not go on after a low blow brought his WBO welterweight title challenge against Terence Crawford to a crashing halt.

The fight was stopped in the sixth round at Madison Square Garden after the technical knockout, handing the American the right to retain the belt and raising a cacophony of boos for Khan.

"He was looking for a way out," Crawford said. "I saw him shaking his head and talking to his trainer and I thought oh hell I know he's going to quit. I don't like to win a fight like that."

Khan said he could feel the blow in his stomach and his legs “kind of seized” as a result.

"I don't quit and I didn't quit. Crawford is a great fighter and if people want to say I quit its up to them," Khan said,

Crawford was unequivocal that his shot was not enough to end the fight and the decision to withdraw was Khan’s.

"'You didn't quit? Tell the truth," Crawford said to Khan.

The Briton suffered a knockdown in the opening round and was taking regular punishment, struggling to stay in the contest and nursing what appeared to be an injury to his right hand.