Former world heavyweight champion Wladimir Klitschko said Wednesday he will take up the contractual option of a rematch against Tyson Fury in an attempt to win back his belts. Britain's Fury, 27, stunned Klitschko last Saturday at Duesseldorf's Esprit Arena with a unanimous points defeat, his first loss for 11 years, which ended the Ukrainian's nine-year reign as world champion. Hamburg-based Klitschko, who turns 40 next April, says he banished thoughts of retirement in the wake of the shock defeat. He has vowed to use his chance to win back the IBF (International Boxing Federation), World Boxing Association (WBA) and World Boxing Organization (WBO) belts he deservedly lost to Fury in a poor performance. "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. "I couldn't show my full potential at any time. This is what I want to change in the rematch - and I will. Failure is not an option." Klitschko's manager Bernd Boente said they will now open negotiations with the Fury camp to decide the venue and date. "There will be a huge worldwide interest in this fight which already can be billed as the fight of the year 2016," said Boente. "We received so many questions of fans and journalists after last Saturday. "The new champion and his challenger will answer all of them inside the ring." Klitschko, who is 1.98-meters (6-foot-6), was in the unusual position of facing someone taller. Fury, who weighed in at 112 kilograms (247 pounds) also had half-kilo (1.1 pound) weight advantage for the fight. The Ukrainian dropped to 64-4, with 53 KOs, while Fury improved to 25-0, with 18 KOs.