|Klitschko was already the IBF, WBO and IBO champion, and added Hayes WBA belt with the win [AFP]
Ukrainian Wladimir Klitschko has beaten Briton David Haye in a world heavyweight boxing reunification title fight, taking the bout by a unanimous judges' decision and becoming the undisputed heavyweight boxing champion of the world.
Klitschko, the IBF, WBO and IBO world champion, adds the WBA title to his heavyweight belt collection with his win in the fight on Saturday.
The victory at the rain-soaked SV Hamburg football stadium in Germany means that Klitschko and Vitali, his older brother, now hold all three major heavyweight world titles.
All three judges named Klitschko as the winner, scoring the 12-round bout 117-109, 118-108 and 116-110.
Haye, who stirred most of the hype ahead of the fight with a series of statements, said that he had hurt a toe in his right foot while training, and lost some of his power because of it.
"I couldn't give everything I needed to, it was really frustrating," Haye said in the ring. "I had to knock him out and unfortunately I couldn't do it."
Haye slipped to the canvas repeatedly as he tried to get in close with the heavier, taller and more experienced Klitschko.
Genaro Rodriguez, the referee, began counting Haye on one of those occasions, in the 11th round, but he was quickly able to get back to his feet.
The Briton came out swinging in the final round, landing a series of body blows but never really troubling the Ukranian.
Klitschko stayed behind his much-feared left jab for most of the fight, and landed a right on Haye's chin in the fifth round.
The Ukrainian weighed in 30 pounds heaviers than Haye ahead of the fight, tipping the scales at 243lbs to the Briton's 213lbs.
Haye had said that he was happy with his weight, describing it as as his "ideal, perfect fighting weight".
He had earlier been involved in "trash talking" the Ukranian, but Klitschko said he was not put off by Haye's jibes.
"I've been called a dead man walking before. But this dead man keeps walking..." he said.
Indeed Klitschko said that he had enjoyed the atmosphere that had developed around the fight, saying that he enjoyed the attention and buzz which he credited Haye with creating.
Klitschko had won the IBF belt against Chris Byrd in 2006, and added the WBO title two years later. Haye had been WBA champion since 2009.
This was the first heavyweight unification fight since the Ukranian took the WBO belt from Sultan Ibragimov at Madison Square Garden in 2008, and was the biggest title boxing match since Mike Tyson was beaten by Lennox Lewis in 2002.
The win gives Klitschko 56 wins out of 59 professional fights, with just three defeats. Hayes, meanwhile, has a record of 25 wins (23 by knockout) and two defeats.