MOSCOW (Reuters) - Vladimir Klitschko retained his world heavyweight titles with a unanimous points victory over Russian Alexander Povetkin at the Olimpiyskiy Stadium on Saturday. The 37-year-old Ukrainian, who took his record to 61 wins and three defeats, knocked Povetkin down four times on the way to retaining his WBA, IBO, IBF and WBO crowns. Klitschko's older brother Vitali holds the WBC belt. "Alexander is a fighter and it was hard for him because I hurt him. But he stuck in there because he has a big heart," said Vladimir in a ringside interview. "I wanted to finish it earlier. ... Click here to read full news..