GELSENKIRCHEN, Germany (AFP) - After retaining his IBF and WBO titles by stopping challenger Ruslan Chagaev on Saturday, world heavyweight champion Wladimir Klitschko labelled Britain's David Haye 'unprofessional'.

Chagaev suffered the first defeat of his career when he was unable to come out for the tenth round after suffering a cut eye and the referee called off the fight to give Klitschko his 53rd win to retain his titles.

But Klitschko had been scheduled to fight British former cruiserweight Haye -- who had taunted the champion by calling him 'Bitchko' -- at the Veltins Arena until a back injury forced Haye out and Chagaev stepped in.

"I am very upset about David Haye, he has a big, bad and dirty mouth, I can not rely on this man, he is immature as a fighter and immature as a person," fumed Klitschko.

"I missed a fight in April to accommodate him, he couldn't deliver Chelsea (Stamford Bridge), so we moved the fight here.

"There is no blame on him physically, a fighter's health is important and boxers get injured.

"But he kept telling journalists then he needed two more weeks to recover, then he needed three, four weeks, I just kept hearing he needed more and more time.

"I have never worked with such unprofessional people, there was no official medical statement from his team.

"If he wants to fight me now, no problem, get in frigging line, I think he will end up on the floor."

With elder brother Vitali holding the WBC heavyweight title, the Klitschkos hold three belts and only WBA champion Nikolai Valuev stands in the way of them dominating the weight division totally.

"Nikolai Valuev was the first boxer we asked when Haye pulled out and he was also the first fighter who said 'no'," said Klitschko.

"Ruslan Chagaev didn't take too long to accept the fight and respect to him for that.

"I will come back to box here and I also want to box at Madison Square Gardens again."

On the night, Chagaev, the WBA heavyweight 'champion in recess' was no match for the might of Klitschko who lived up to his 'Dr Steelhammer' nickname to put the challenger on the canvas as early as the second round.

And Klitschko says his best is yet to come.

"That wasn't my best fight, that is yet to come both for me and my brother," said the Ukrainian.

"I was ready for (Russia's 2004 Olympic gold medallist) Alexander Povetkin, but he pulled out with his injury last year, but I would like to give him a chance again.

"I believe the Klitschko brothers have almost all the belts and I am just enjoying the process, I am not thinking of my legacy, I just want to find the best fighter in the world and beat him."

This was Klitschko's 53rd win to retain both his world titles against hepatitis B sufferer Chagaev, who was forced to call off last month's WBA title decider against Valuev in Finland because of medical concerns.

Chagaev was knocked down in the second round when Klitschko caught him with a straight right which stunned the Uzbeki who sat back on the canvas.

At the end of the ninth round the crowd at the Veltins Arena, home of Bundesliga football side Schalke 04, were on their feet as Klitschko landed several blows to the face and Chagaev was in deep trouble at the end of the ninth.

Klitschko now has an impressive 47 knock-outs from 53 wins fights.

The last of his three defeats as far back as 2004 against Lamon Brewster in Las Vegas when he lost the WBO title he later regained against Sultan Ibragimov in Madison Square Garden, New York, last year.