Hamburg, Oct 17 - Ukrainian WBC champion of the world Vitali Klitschko has retained his heavyweight title with an unanimous points victory over challenger Shannon Briggs.

Although the American had said before the fight Saturday that he would knock out the champion, who boxes out of Germany, the 38-year-old was never in it and probably lost all 12 rounds.

A capacity 14,500 crowd in the Hamburg 02-Arena saw Klitschko come close to putting Briggs on the floor. But knowing that the American is a powerful puncher, who has managed to win 45 of his 51 victories by knock-out, the 39-year-old had to keep his guard.

Klitschko was so dominant throughout the fight that Briggs' corner must have come very close to throwing in the towel as their fighter was taking punishment.

Briggs, who said before the fight that he was going to knock-out Klitschko, admitted later that it was his most difficult fight.

"Klitschko is a real champion and deserves to be in the Boxing Hall of Fame."

Klitschko paid a tribute to his opponent. "I was surprised that he could take all my punches. He fought bravely and simply would not go down."

Klitschko's record goes to 38 knock-out wins in 43 fights, with two defeats, while Briggs stands at 51 wins from 59 bouts with six defeats. (dpa)