Kell Brook revealed he defied his team's wishes to return to welterweight and accept the challenge of facing unbeaten American Errol Spence Jr for his World title.
Eight months on from stepping up two classes for a loss to Gennady Golovkin at middleweight, Brook has lost those 13 pounds to get back to the division where he owns the IBF World belt that he will defend against Spence at Sheffield's Bramall Lane tonight.
The 147lb-limit, which 31-year-old Brook was inside at yesterday's weigh-in, has therefore been even more challenging thanks to a gruelling 12-week camp in Fuerteventura.
Yet Brook claimed his determined nature was the reason he ignored advice from those close to him, with a desire to hang on to his belt overriding anything else.
"I've put myself through it," he said of his preparations to face Spence. "My team wanted me to move up to 154 (pounds) but I'm a stubborn guy, it took me all my career to get that World title.
"There's no way that I want to move up and just give that title up. You've got to take it away from me, rip it out of my hands. I'm passionate and this belt belongs with me.
"I've made sure I've put myself through it. I got on top of my weight early in camp so I came here fit and healthy."
Spence may be the challenger, but he has been made the favourite to dethrone Brook in South Yorkshire thanks to an impressive 21-0 record that has seen the hype surrounding him rise.
Brook's counter to such odds is that none of his challenger's previous opponents could hold a candle to him.
"I love a challenge; I've proven these guys wrong before and I'm going to do it again," he confidently declared.
"There are question marks over Errol Spence, he's never been in with a guy like me. There's question marks and we're going to get them answered.
"He's a very good fighter. Our styles are going to gel. I think there's going to be a lot of drama in this fight. We'll both maybe hit the canvas.
"This fight is going to be a thriller, fireworks from round one, he's not going to take a backward step and I'm not."