-- Wladimir Klitschko revealed that "losing feels good" as he reflected on his defeat to Tyson Fury in November.
Klitschko, 40, had gone almost 12 years unbeaten and made eight successful defences of his WBA, IBF, WBO and IBO heavyweight titles before Fury outpointed the Ukrainian in Dusseldorf.
The pair will meet in a rematch on July 9 in Fury's hometown of Manchester but, speaking to BBC Sport about the initial fight, Klitschko said: "I'm glad that my hand was not raised that night.
"Failure is not an option unless it is the only way to get better, and I had to get better. I needed a push to get better and I got it. I feel it.
"Losing feels good. I didn't show my full potential in the fight. Physically I was in one of my best shapes, but mentally I wasn't there, not present in the ring.
"After a while, you get used to defending and not conquering the man in front of you. It will be different on July 9.
"I had no failures for 11 and a half years. After a while it's OK to make a mistake and I made a mistake against Fury. I want to make that clear in my revenge and it is what I'm looking forward to."
Since Klitschko's defeat, the major heavyweight titles are now spread across Fury (WBA and WBO), Deontay Wilder (WBC) and Anthony Joshua (IBF). Up until Klitschko's brother Vitali retired in 2013, all titles had been held by the siblings.
"Before, it was clear: one champion, one family name," Klitschko added. "When the chef is not in the kitchen, the belts get lost -- Fury, Wilder, Joshua.
"When the chef leaves, the rats dance on the table. I want to show who the chef is in this kitchen."
Before denouncing all talk of his own retirement as "not true", Klitschko was equally dismissive of Fury's decision to attend the original fight's pre-match press conference dressed as Batman.
"In our big boxing family we have some characters," he said. "I've faced different press conferences with T-shirts and freaks. You don't win at a press conference.
"It's better to deliver it on July 9. It's not a rematch -- it's revenge."
Klitschko also revealed he has "always been a fan" of Joshua.
London-born Joshua, who rose to prominence by winning gold at the 2012 Olympic Games, won the IBF title of which Fury had been stripped due to his refusal to fight mandatory challenger Vyacheslav Glazkov.
"There are so many champions but that's no disrespect to Anthony Joshua," Klitschko added. "He's a talented guy that will conquer the division for a long time.
"He still has a lot to learn, but I'm putting a lot of hope in him. He will represent the heavyweight division better than Tyson Fury."