The 38-year-old Klitschko, who has been world champion since 2006, defends his WBA, IBF, WBO and IBO belts in Oberhausen, Germany, on Saturday against Australian challenger Alex Leapai.

Leapai, 34, has a 30-4-3 career record since turning professional in 2004, while Klitschko is 61-3 with 51 knock-outs and his last defeat is now a decade ago.

Klitschko has said he has no plans to retire and wants to break US boxing legend Louis’s record of 12 years as a world heavyweight champion, having been unbeaten between 1937 and 1949, with the Ukrainian needing to fight on for four more years time until 2018, when he will be 42.

“I just turned 38, but that’s only a number,” Klitschko told German daily Die Welt on Sunday.

“I am still extremely hungry and better than ever. A few years ago, I thought I couldn’t improve, but my mission is still a long way from over. I want to box on for ten more years.

“I feel the combination of experience, athletic-ability, technique and strategy makes me the complete professional.”

Ukraine-born Klitschko admits it is challenging to prepare for his 65th professional fight with his brother Vitali in the thick of their country’s volatile political situation in Kiev.

“It’s a bizarre situation,” said Wladimir.

“My body has been training at the camp in Austria, but my mind is often with my brother and our compatriots in Ukraine.”