Vladimir Klitschko retained his IBF world heavyweight title by beating Ray Austin on a technical knockout in the second round on Saturday night.

Ukrainian Klitschko, 30, landed a series of vicious left punches that sent the hapless American challenger into the ropes and then crashing to the floor.

Austin, 36, staggered to his feet but the referee, Eddie Cotton, ended the scheduled 12-round bout.

It was Klitschko's second successful defence of the title he won in April last year by defeating American Chris Byrd.

The win took the 6-foot-6 (1.98 metres) tall Klitschko's record as a professional to 48 wins, including 43 knockouts, and three losses.

"I have prepared hard," Klitschko said. "He was a mandatory challenger. I am happy about the win. I hope the crowd is happy, too. It was short but it was heavyweight boxing."

Klitschko revealed that comments from Austin and his promoter Don King had helped motivate him. "I did 120 rounds of sparring with different sparring partners and I was very motivated by the comments made by Ray Austin and his promoter Don King before the fight," Klitschko said.

"I was surprised he got back to his feet and the referee was right to stop it because he could not continue any more.

"As for the next fight for me, I would like Nikolay Valuev."