Terence Crawford retained his welterweight title by technical knockout Saturday night when Amir Khan wasn't able to continue after being hit with a low blow in the sixth round.
Crawford threw a left hand that hit Khan on his right hip and Khan retreated toward his corner in pain. After taking a couple minutes trying to shake off the pain, his corner told the referee that Khan couldn't continue.
Crawford (35-0, 26 KOs) had knocked Khan down in the first round, but the final couple rounds had been competitive, with both fighters throwing hard shots from close range.
Referee David Fields didn't appear to see the final one that hit Khan (33-5) low. Khan could have taken five minutes trying to recover, but his trainer, Virgil Hunter, made the decision before then that Khan was finished.
"I didn't want to send him back out there when he didn't have his legs," Hunter said.
Crawford was ahead 49-45 on two judges' cards and 50-44 on the other when the fight ended to loud boos from the crowd of 14,091 at Madison Square Garden.
"I could tell I was breaking him down. It was just a matter of time," Crawford said. "I just took my time. I was disappointed the corner stopped the fight in that manner, but Virgil is a great coach, and he was looking out for his fighter. I know he didn't want to go out like that."
Crawford started fast in the second defense of his WBO version of the 147-pound belt, throwing a short right hand followed by a left that sent Khan to the canvas. He hurt Khan again late in the round and had no trouble controlling the early part of the fight.
They both threw hard shots in the fourth and Khan landed some of them in his best moments of the fight. But Crawford hit him with a pair of good lefts in the fifth and was scoring again in the sixth when his final punch accidentally drifted low.
Khan, the 2004 Olympic silver medalist from Britain, was looking for what could have been the biggest of his pro career. The former 140-pound champion could have looked to fight fellow British star Kell Brook in perhaps a more lucrative and winnable opportunity, but instead took the opportunity at Crawford, the Omaha, Nebraska product widely considered one of the best fighters in the world.