Dr. Steelhammer

The referee ended the bout in Mannheim on Saturday, Dec. 13, when Klitschko trapped the somewhat smaller Rahman in a corner, landing a series of punches to his head. The Hamburg-based Ukrainian had already knocked his opponent down in round six.

Bagging the victory with ease, 32-year-old Klitschko earned the right to keep his WBO, IBF and IBO world heavyweight titles.

"I thought I could land some punches earlier but it wasn't worth it because Hasim Rahman knew he was up against the best and he was really focused, you could see that," said Klitschko, who has been dubbed "Dr. Steelhammer."

Rahman, 36, shot to fame when he knocked out reigning WBC, IBF and IBO champion Lennox Lewis in 2001. He stepped in at the last minute to face Klitschko when Russian Alexander Povetkin withdrew due to injury.

Klitschko landed several key punches in the first two rounds and, in the third, Rahman spent most of the time of the ropes. Despite visibly loosing steam, he stood up after being knocked to the canvas in the sixth round. But the champion only needed 44 seconds in the seventh before the referee blew the whistle.

After completing his sixth title defense, Klitschko now has 52 wins and three defeats. Rahman has slipped to 45 wins, seven defeats and two draws.

With three titles to his name, Klitschko and his brother Vitali, who is the WBC champion, have their sights set on the WBA belt next year.