Wladimir Klitschko Universum Box-Promotion in Hamburg under the tutelage of Fritz Sdunek, often being featured on fight cards alongside his elder brother Vitali. After building an undefeated record of 24–0 with 22 KOs, he suffered his first loss to 24–13–1 Ross Puritty, in what was Klitschko's first and only professional fight in Ukraine. Puritty forced Klitschko, who had at that time not gone beyond 8 rounds, to punch himself out. Klitschko began to be overwhelmed in the 10th round and went down twice but was allowed to continue. At the start of the 11th round, with Puritty continuing to land hard punches,
Lennox Lewis vs. Vitali Klitschko 2003 to determine who would face Lewis next. Klitschko easily dispatched Johnson, winning by second-round technical knockout, to set up a rematch with Lewis. However, rather than proceed with his rematch with Klitschko, Lewis announced his retirement two months later on February 7, 2004, vacating his titles in the process. Two months later, Klitschko met the WBC's number two ranked contender and then-reigning WBO champion Corrie Sanders, who had defeated Klitschko's brother Wladimir earlier in 2003, for the vacant WBC and "The Ring" Heavyweight titles. Klitschko defeated Sanders, who relinquished his WBO title to fight Klitschko, by eighth-round technical knockout