Russian challenger Sultan Ibragimov beat America's Shannon Briggs on points to claim the World Boxing Organisation heavyweight title in Atlantic City.
Ibragimov's convincing win took his career record to 21 wins, one loss
Briggs, making his first defence of the title, towered over the 32-year-old Russian but the 2000 Olympic silver medallist won a unanimous decision.
The judges scored it 119-109, 117-111 and 115-113 in favour of Ibragimov.
"Shannon Briggs is a very tough guy and I respect him but tomorrow I will wake up a champion," said Ibragimov.
The fight was originally scheduled for 10 March in New York but was postponed when Briggs went down with a case of pneumonia.
And the former champion claimed he was still feeling the effects, saying: "I have been taking all kinds of antibiotics. I couldn't train for the last two weeks.
I really didn't want to fight, but if I pulled out they threatened to sue me and they would have stripped me (of the title)
"I really didn't want to fight, but if I pulled out they threatened to sue me and they would have stripped me (of the title)."
Ibragimov began cautiously but quickly found his range against the flat-footed Briggs and repeatedly caught the 35-year-old.
The bout, lacklustre throughout, was lit up in the ninth round when Ibragimov caught Briggs with a series of combinations and he knocked his opponent to the canvas in the following round.
Despite knowing only a knockout could save him, the Amercian failed to launch a late assault and the title went to Ibragimov.