Klitschko knocks out Chambers to retain titles

World heavyweight champion Vladimir Klitschko landed a left-hand knockout punch five seconds from the end of the fight to beat challenger Eddie Chambers and retain his WBO, IBO and IBF belts on Saturday night.

Ukrainian Klitschko, 33, rattled the 27-year-old American in the second round but had to wait until just before the end of the 12th to stage a dramatic finale and knock him out in front of 51,000 fans at Duesseldorf's soccer stadium.

Chambers tumbled into the ropes with the referee ending the bout as Klitschko improved his record to 54 wins from 57 fights.

"I have to give him credit. Chambers is very fast and super strong," Klitschko said.

"He does not have much punching power but could have probably outboxed me if I had got tired."

Both boxers started off cautiously with Klitschko well aware of "Fast Eddie" Chambers's speed and the American wanting to avoid the Ukrainian's reach.

It did not take long, though, for the 1996 Olympic champion to hurt Chambers with a series of punishing right-hand punches in the second round that rattled his confidence.

Chambers landed few big punches and none powerful enough to hurt Klitschko. The American looked more interested in avoiding the Ukrainian's knockout punch that had already claimed 47 victims.