Tony Bellew hailed Oleksandr Usyk and confirmed he was retiring after losing to the Ukrainian in Manchester on Saturday.
Bellew, 35, was stopped in the eighth round by Usyk, who retained his cruiserweight titles and perfect record.
The Brit, who confirmed his retirement, was full of praise for the 16-0 Usyk.
"He's an exceptional fighter who deserves all the awards in the world. I lost to one of the pound-for-pound best," Bellew told Sky Sports.
"I have no excuses. He is an amazing fighter.
"He is the greatest man I have ever shared a ring with. I wish [him] greatness. I'm a world-class fighter, but that was the difference between world class and elite level."
I tried my best and gave it everything I had! You my friend @usykaa are a great champion and the best fighter I have ever faced. You beat me fair and square.. I only wish you well going forward and thank you for the opportunity.
— Tony Bellew (@TonyBellew) November 11, 2018
The fight was the third of the year for Usyk, who added the WBC, WBA and IBF titles to his collection to become the unified cruiserweight champion.
But the 31-year-old said he was in desperate need of a rest after a big 2018.
"This has been a very successful year but it has also been the toughest year of my career. So right now my primary concern is my rest," Usyk said.
"And I want to spend some time with my family."
