Amir Khan became the unified world light-welterweight champion with victory over Zab Judah at the Mandalay Bay Events Centre in Las Vegas.
Khan, who was defending his WBA belt, took Judah's IBF title thanks to a fifth-round stoppage, which crowned a superb performance.
The 24-year-old Englishman landed a powerful right uppercut to the body of Judah, who was counted out after dropping to the canvas in pain.
Judah claimed that he had been struck below the belt, but replays showed that the shot landed on the belt line, confirming that it had been a legitimate strike.
"He went down and it was above the belt," Khan told BBC Radio 5 live. "It was nowhere near below the belt, it was a great shot."
Judah disagreed with his conqueror, claiming that “everyone in world who saw the fight will see that's a low blow."
However, Judah would find it hard to argue that he had beaten by the better fighter on the night, after Khan had dominated the affair with the American constantly on the back foot and struggling to deal with his opponent’s hand speed.
A delighted Khan paid compliment to his rival following the victory, saying: “Zab's a great fighter. I respect him a lot."