Bulgarian Kubrat Pulev is angered by any suggestion that he could step aside and allow Anthony Joshua take on Tyson Fury.
Pulev is the mandatory challenger for unified champion Joshua's IBF world title, but their planned bout for 20 June was postponed due to the coronavirus pandemic.
That led to promoter Eddie Hearn suggesting that if Pulev and WBC champion Tyson Fury's next opponent Deontay Wilder stepped aside, Joshua could then meet Fury.
Hearn has since backtracked on that proposal but Pulev still is not happy about the idea being floated.
"I wouldn’t accept it. "I did it once when I didn’t have to do it for him (Joshua) to have his second match against Ruiz Jr.," Pulev told Reuters.
"Everything was against IBF’s rules, but I compromised."
Joshua and Pulev were originally meant to clash at Cardiff's Principality Stadium in 2017 but the Bulgarian brusier was forced to pull out after he injured his shoulder.
The 30-year-old Londoner has held the IBF, WBA, WBO and IBO since beating Andy Ruiz Jr in a December rematch in Saudi Arabia.
Hearn was hoping to reschedule the Pulev bout later in the summer but admits he may now have to make the fight between October and December.
The 39-year-old is losing patience and aimed some insults at the British champion.
"Enough is enough. I can’t understand why we are still postponing instead of fixing a date and venue and getting to work? I can’t wait to win this fight," Pulev added.
"I see how people are afraid of me and are trying to face someone else before me. That’s not how a real world champion should act.
"Even Mike Tyson and Evander Holyfield are coming back to the game to show that they are real warriors, not like him. A year has passed, and they always have a reason to postpone, not to fight against me.
“There are two options. You either fight or vacate the title.”
The Bulgarian has 28 wins from 29 bouts, while Joshua has 23 wins from 24.