Wladimir Klitschko retained his WBO heavyweight title on Saturday to remain on a collision course with Lennox Lewis.

The Ukrainian came out on top against Jameel McCline in Las Vegas when the American did not come out for the 11th round after being knocked down late in the 10th.

"He was tough but simple," said Klitschko. "If he had come out for the next round I am sure I would have ended the fight very quickly."

He was physically strong but he never landed a heavy punch Wladimir Klitschko on Jameel McCline

Klitschko is regarded as the biggest challenge remaining for Lewis, who will take on Klitschko's brother, Vitali, in March.

The WBC champion will then target Mike Tyson in a rematch before a unification showdown with Vladimir.

Klitschko won nine of 10 rounds on two scorecards and eight on the third against McCline, a top-ranked and respected opponent.

"The plan was to take my time and take minimum risks," said Klitschko, the 1996 Olympic gold medallist.

"I used my head in the ring because I want to use my head again in the future."

"He was physically strong but he never landed a heavy punch."

Klitschko landed two left hooks, another left and then a right that put McCline on the canvas in round 10.

McCline got up at the count of nine as the bell sounded to end the round, but his corner would not allow him to continue.