Wladimir Klitschko - a dominant figure in boxing heavyweight's division for much of the 21st century - has announced his retirement at the age of 41, meaning an anticipated rematch with Anthony Joshua will not take place.
After winning a gold medal for Ukraine at the Atlanta Olympics in 1996, Klitschko forged a hugely successful professional career that saw him rule supreme in the heavyweight ranks, together with elder brother Vitali.
An 11-year unbeaten streak, featuring 18 successful title defences, was brought to a stunning end in November 2015, when Klitschko suffered a shock points defeat to Tyson Fury in Dusseldorf.
Klitschko was also beaten by Joshua at Wembley Stadium in April, in what has proved to be the former's last fight. Yet there was much to admire from the veteran's performance as he courageously climbed off the canvas to fell Joshua, before eventually being stopped in the 11th round of an epic encounter.
Having been hailed for his impressive display in defeat, Klitschko had been expected to face Joshua again in Las Vegas later this year, with the Briton's promoter, Eddie Hearn, stating as recently as Wednesday that a rematch could be confirmed by next week.
Instead, one of boxing's most decorated heavyweights - boasting a record of 64 wins and five defeats from a 21-year professional career - has opted to step away from the ring.
??? ???????. ?????? ?????: https://t.co/zi6sWV7I70-- Klitschko (@Klitschko) August 3, 2017
Confirming the decision in a video posted on his official YouTube channel, Klitschko said: "Twenty-seven years ago I started my journey in sport and it was the best choice of a profession I could have ever made.
"Because of this choice, I've travelled the world, learned new languages, created businesses, built intellectual properties, helped people in need, became a scientist, entrepreneur, motivator, hotelier, trainer, investor and much else.
"At some point in our lives, we need to, or just want to, switch our careers and get ourselves ready for the next chapter and chart a new course towards fresh challenges. Obviously I'm not an exception to this. And now [it] is my turn.
"I'm honestly doing this with the greatest respect for the new challengers, but also with tremendous excitement, passion, dedication, expecting and hoping that my next career, which I've already been planning on working on for some years, will be at least as successful as my previous one, if not even more successful."