Terence Crawford retained his welterweight world title and remained undefeated with a sixth-round TKO after Amir Khan could not continue following an accidental low blow.
The blockbuster bout in New York came to an anti-climactic end after a shot below the belt left Khan unable to carry on against the WBO holder on Saturday.
Khan (33-5) was hit early in the sixth round at Madison Square Garden, where the referee waved off the fight at the request of the Englishman.
While the crowd were left disappointed amid a chorus of boos, Crawford improved to 35-0 after the bout ended at the 0:47 mark.
"I could tell I was breaking him down," Crawford said inside the ring. "It was just a matter of time. I just took my time. I was disappointed the corner stopped the fight in that manner, but Virgil [Hunter] is a great coach, and he was looking out for his fighter. I know he didn't want to go out like that."
Crawford – rated one of the best pound-for-pound boxers in the world – was on the front foot following in the opening round, which saw the unbeaten boxer drop Khan in New York.
Khan landed a couple of jabs but Crawford suddenly caught the Brit with a counter right with a minute remaining – flooring his opponent.
Crawford almost sent former unified light-welterweight champion Khan to the canvas again before the bell rang and the 32-year-old dug deep from that point.
Khan was more defensive in the second as he struggled to find an opening, though he lunged with a lead left hook that Crawford took well.
Crawford – who switched to a southpaw stance – waited patiently for the killer blow and he made some inroads in the fourth, targeting the body as he stalked Khan.
The 31-year-old Crawford broke down Khan with more heavy hitting in the fifth and the fight came to a premature end a round later as the latter's corner informed the referee that their boxer could no longer continue.