Manuel Charr has vowed to knock out Briton David Haye and set up a rematch with world champion Vitali Klitschko.
Charr lost to Klitschko last September, although the fight was stopped due to a cut.
The German insists he would have won the contest had he been allowed to continue but now faces a battle to get back into world-title contention.
He hopes to do so by beating Haye when they meet in Manchester on June 29
Charr said: "Vitali doesn't want to fight David and he doesn't want to fight me again, either.
"But if Vitali is any sort of champion he will look at this fight on June 29 and then fight the winner. We both want him and we have both earned the right to get a shot.
"He's never fought David Haye, and Haye has called him out for three years now. Vitali said he wanted to knock him out, shut him up and all this other rubbish, but he never did anything about it. The fight has never happened.
"I won't let Vitali do the same to me. I want my rematch and to get it I have to knockout David Haye on June 29. So that is exactly what I will do."
Haye, who lost his WBA world title to Klitschko's brother Wladimir in 2011, will be making his first ring appearance in 11 months when he steps in with Charr and will be looking to inflict only the second defeat of the 28-year-old's career.