The IBF cruiserweight champion has experienced a lot of ups and downs over the years and admitted he thought he was finished when he got "chubby and fat" during a lengthy layoff – but just a year later, he beat Mairis Briedis to gain his world title.

He told Boxing News magazine: "I know I deserve to be here because I've been through those spots.

"Those low points, and that one was not the only one.

"Eating through a straw for four months was one too.

"These are mental games. I've been there and picked myself off the ground so now I know what I have to do.

"Even when I broke my hand, I was in a cast for nine months and was like 117kg.

"I was coming bac k from injury. I thought my career was over and that was the fight before Briedis.

"I went and got surgery and was in a cast for nine months and I just got really chubby and fat.

"I was drinking and all of that. I was a nobody then.

"I remember my first session back, I went in the gym and did two rounds of skipping. Punched the bag for two rounds and then I sat down and just said, 'My career is over.'

"I honestly thought that was it… but 12 months later, I beat Briedis. The emotional rollercoaster I've been through is f****** insane."

And that wasn't the first time Jai had feared the end for his boxing career as in summer 2018, he and his dad Tapu, who is also his trainer, considered walking away for financial reasons.

He said: "We just had no coin, we'd had a s*** day and we were talking like, 'What's the f****** point of this?' Both of us were talking about giving up boxing and just signing up for a local footy club.

"We had given boxing everything we had, but we were getting nothing in return.

"People don't know the rollercoaster I've been on.

"Remembering moments like that from where I am now just shows the fruits of the labour. It makes everything sweeter."