Britain's Amir Khan added the IBF light-welterweight title to his WBA crown with a fifth round knockout of Zab Judah in Las Vegas.
The fight ended with 13 seconds remaining of the fifth round when the 33-year-old American was floored by a body shot at the Mandalay Bay Resort.
Referee Vic Drakulich, who was standing behind Judah, counted him out as he rolled around on the canvas before latterly complaining it was a low blow.
Judah, 41-7, who has won world titles at light-welterweight and welterweight, was also hampered by an accidental headbutt in the first round but had clearly lost all five rounds and replays suggested his complaints were not legitimate.
Khan's performance was as impressive as when he claimed a thrilling unanimous points decision win over Argentine Marcos Maidana at the same venue in December.
Khan, who improves to 26-1 with 18 knockouts, overwhelmed Judah with his superior speed and precise punching.
The Bolton fighter scored with several solid flurries, backing Judah to the ropes and landing right hands that had the largely British crowd roaring with approval.
Blood was pouring from Judah's face when the fight ended after the veteran was caught on the waistband - which was pulled up high - and despite knowing there was no standing eight count, he failed to get back to his feet.
"I was headbutted in the first round and it was a low blow in the fifth. I thought he was giving me time to get up. I didn't understand the finish," Judah said afterwards.
The victory sets up the prospect of a possible blockbuster clash with undefeated welterweight Floyd Mayweather next year for Khan but the possibility of a title unification fight bout with WBC and WBO champion Timothy Bradley looks distant.
Richard Schaefer, CEO of Golden Boy Promotions, suggested that a December fight with Mexican veteran Erik Morales would be Khan's most likely next fight.
"Tonight was the biggest victory in Amir's career. We really don't need to fight Timothy Bradley, he needs us more than we need him. Amir is the king of the division. I really don't think Bradley wants anything to do with Amir after the performance. He has moved onto a new level," said Schaefer.
Khan can now add Judah's name to his list of top scalps in the division - following victories over Marco Antonio Barrera, Andreas Kotelnik, Paulie Malignaggi and Maidana - and he was delighted.
He said:
The fight ended with 13 seconds remaining of the fifth round when the 33-year-old American was floored by a body shot at the Mandalay Bay Resort.
Referee Vic Drakulich, who was standing behind Judah, counted him out as he rolled around on the canvas before latterly complaining it was a low blow.
Judah, 41-7, who has won world titles at light-welterweight and welterweight, was also hampered by an accidental headbutt in the first round but had clearly lost all five rounds and replays suggested his complaints were not legitimate.
Khan's performance was as impressive as when he claimed a thrilling unanimous points decision win over Argentine Marcos Maidana at the same venue in December.
Khan, who improves to 26-1 with 18 knockouts, overwhelmed Judah with his superior speed and precise punching.
The Bolton fighter scored with several solid flurries, backing Judah to the ropes and landing right hands that had the largely British crowd roaring with approval.
Blood was pouring from Judah's face when the fight ended after the veteran was caught on the waistband - which was pulled up high - and despite knowing there was no standing eight count, he failed to get back to his feet.
"I was headbutted in the first round and it was a low blow in the fifth. I thought he was giving me time to get up. I didn't understand the finish," Judah said afterwards.
The victory sets up the prospect of a possible blockbuster clash with undefeated welterweight Floyd Mayweather next year for Khan but the possibility of a title unification fight bout with WBC and WBO champion Timothy Bradley looks distant.
Richard Schaefer, CEO of Golden Boy Promotions, suggested that a December fight with Mexican veteran Erik Morales would be Khan's most likely next fight.
"Tonight was the biggest victory in Amir's career. We really don't need to fight Timothy Bradley, he needs us more than we need him. Amir is the king of the division. I really don't think Bradley wants anything to do with Amir after the performance. He has moved onto a new level," said Schaefer.
Khan can now add Judah's name to his list of top scalps in the division - following victories over Marco Antonio Barrera, Andreas Kotelnik, Paulie Malignaggi and Maidana - and he was delighted.
He said:
