World heavyweight champion Vladimir Klitschko defended his WBO and IBF belts on Saturday with a technical knock-out of United States challenger Hasim Rahman in the seventh round.

Klitschko, known as Dr Steelhammer, needed just 44 seconds of the seventh as he used his powerful jab to impressive effect before the referee was forced to intervene to stop in favor of Klitschko in Mannheim of Germany.

The champion had been due to face Alexander Povetkin here, but a training injury ruled the Russian out and former champion Rahman,"The Rock" from Baltimore, stepped in as a late replacement - but he was out-classed.

The 36-year-old, who pulled off the boxing shock of the year in2001 when he knocked out reigning WBC, IBF and IBO champion Lennox Lewis, was marked from a Klitschko punch as early as the second round.

He spent most of the third on the ropes and rarely threatened the champion.

Klitschko, 32, had spent the last six weeks in Majorca training for the fight and picked his punches carefully with his left jab was a constant source of punishment for Rahman.

The champion had the American on the canvas in the sixth round with a series of jabs before the powerful right fist caught the challenger on the chin and although Rahman survived the count, he was obviously struggling from then on.

It was a huge left to the side of the face which ended the fight early in the seventh.

The champion Klitschko has now won 52 of his 54 professional fights with 46 knock-outs, while for Rahman this was the seventh defeat in his 55th fight, who has won 45 fights with 36 knock-outs and lost six times.

(Xinhua News Agency December 15, 2008)