Boxing: Klitschko edges 'tough contest'

World heavyweight champion Vladimir Klitschko was made to go the distance against Polish challenger Mariusz Wach in Hamburg but earned an unanimous points decision on Saturday to retain his four title belts.

The 36-year-old Ukrainian, who holds the IBF, IBO, WBO and WBA crowns, was never seriously troubled by the 32-year-old who lost his unbeaten record after 27 wins in 27 fights. Klitschko's older brother Vitali holds the WBC crown.

"It was a very tough fight and Mariusz had to take a lot of punches," Klitschko said. "I thought he would go down but he fought on."

Klitschko also remembered late coach Emanuel Steward who died last month. "On 7 July after our last fight we sang happy birthday to him. We miss you, we love you, you are always here in the ring. Thank you Emanuel," Klitschko said.