Ukrainian boxer Wladimir Klitschko knocked out his opponent French Jean-Marc Mormeck in the fourth round in Duesseldorf, Germany, on Saturday, to retain his world heavyweight titles.
Klitschko, 35, nicknamed Dr. Steelhammer, holds the WBA, WBO, IBF and IBO heavyweight belts and has been unbeaten since 2004.
Klitschko entered the bout with 56 wins in 59 professional fights, and picked up his 50th knockout against Mormeck, who dropped to 36-5 after the fight that allowed Wladimir to improve to 57-3.