Wladimir Klitschko has announced his immediate retirement, ending Anthony Joshua's hopes of a rematch in Las Vegas on November 11.
The 41-year-old former world heavyweight champion had been Joshua's preferred opponent for his next title defence but he has instead chosen to bow out on April's dramatic defeat by the reigning IBF and WBA champion.
Joshua is therefore expected to fight mandatory challenger Kubrat Pulev, of Bulgaria, either at Vegas' T-Mobile Arena on the same date or at Cardiff's Principality Stadium on October 28, and does so having been Klitschko's final opponent.
The Ukrainian proved himself the finest heavyweight of his era, during which he won every fight for 11 years and earned the IBF, WBA and WBO titles amid 18 consecutive defences before his 2015 defeat by Tyson Fury.
"I have achieved everything I dreamed of, and now I want to start my second career after sports," he said. "I would have never imagined I would have such a long and incredibly successful boxing career. I'm very thankful.
"I deliberately took a few weeks to make my decision, to make sure I had enough distance from the fight at Wembley Stadium.
"It was the best choice of a profession I could have made.
"At some point in our lives, we need to or just want to switch our careers and get ourselves ready for the next chapter. Now it's my turn.
"Thanks to everyone who has supported me."
Speaking immediately after the Joshua defeat, Klitschko said he would consider his future and that the only fight that could tempt him to continue would be a rematch.