Anthony Joshua and Oleksandr Usyk have until May 31 to agree terms to a fight or purse bids will be called; WBO rejected a delay in ordering this fight from promoter Eddie Hearn; AJ is now set to fight Usyk while Tyson Fury takes on Deontay Wilder again
Usyk, the undefeated Ukrainian who has beaten Tony Bellew and Derek Chisora and formerly held the undisputed cruiserweight title, is now set to challenge Joshua.
"According to my knowledge, AJ is ready to take the challenge," Usyk's promoter Alexander Krassyuk previously told Sky Sports.
"It may happen anywhere including Wembley, but yet no serious venue commitments have been made."
After Deontay Wilder won an arbitration forcing arch rival Tyson Fury to face him next, the undisputed heavyweight super-fight between Joshua and Fury came crashing down after months of negotiations. Fight fans are bitterly disappointed, but promoters Hearn and Arum both say they will rearrange the history-making match in December this year.
Tony Bellew, who was knocked out by Usyk in 2018, told Sky Sports: "He mentally exhausted me in our fight by constantly having his front foot close to mine.
"That doesn't sound much. But it's mental pressure that he puts on you, not physical.
"He wouldn't get involved in any wrestling matches with me. Every time we got close, I would dig him to the body.
"He's vicious and brilliant."
But Chisora, who was outpointed by Usyk in October last year, insisted: "In the heavyweight game, you have to fight, not box."
Joshua has previously said about Usyk: "You've got to let them know that you're there because all that pitty-patty stuff after 12 rounds? Sometimes people don't respect that type of power."
Promoter Eddie Hearn has speculated that the undisputed heavyweight title fight can be rescheduled for December 2021, if Joshua and Fury come through their next fights.
WBC titlist Tyson Fury has been ordered to face Deontay Wilder on July 24 to complete their thrilling trilogy.