Wladimir Klitschko said on Wednesday he will take up the contractual option of a rematch against Tyson Fury in an attempt to win back his belts, just four days after losing them to the Englishman.

Fury, 27, stunned Klitschko last Saturday at Düsseldorf's Esprit Arena with a unanimous points defeat to hand Klitschko his first loss for 11 years and end the Ukrainian's nine year reign as world champion in the process.

The 40-year-old Hamburg-based boxer released the news in the following video on his Instagram account:

"I was really frustrated directly after the fight, but after some short nights I now know that I want to show that I am much better than my performance on Saturday," said Klitschko in a statement, before adding that he was determined to realize his potential and that failure was simply "not an option."

Klitschko's manager Bernd Boente said they will now open negotiations with Fury.

jh/dv (AFP)