The Victorian is on the undercard of the Tim Tszyu-Sebastian Fundora blockbuster fight in Las Vegas on March 31 (AEDT), but has almost as much on the line.

While Tszyu has the chance to add a second belt and emulate his legendary father as a unified world champion, Zerafa is taking on Cuban-American veteran Erislandy Lara for the WBA middleweight title.

Zerafa hasn't fought since November 2022 and was embroiled in an ugly split with his trainer Sam Labruna, then also cut ties with his US promoter.

The 31-year-old was happy to go it alone, but then reconnected with Donaire, who he met at a WBA convention, and the "Filipino Flash" offered to help him prepare for the fight.

Donaire, who has won multiple world titles in four divisions, is still an active fighter but flew to Melbourne to train Zerafa, and will be in his corner at T-Mobile Arena.

"Last year we started connecting and I was like, 'Whatever I can do to help you out, let me know', and then after that he didn't really have any team," Donaire said on a media open day in Las Vegas.

The 41-year-old said he quickly came to realise the talent and ability of the Australian, dubbed "Pretty Boy".

"He's a really nice guy, very respectful, but then getting to know him, I realised how talented he is,'' Donaire said.

"That's when I started to bring out a lot of his talent, a lot of things that I understood in my knowledge and experience in boxing, he was able to comprehend and do the things I was teaching him.

"I've seen my guy, the way he trains, he trains like me, we train like animals, so I know what he's capable of, I know he has every talent and every work ethic to win this fight."

Lara (29-3, 17KOs) is 40 years old but is known as an elusive, slick boxer, and Donaire has warned Zerafa about underestimating his rival because of his age.

"He (Lara) is old, but I'm old too, so don't underestimate us, because I got in the ring with him and he knows I'm still there, so age has nothing to do with it,'' Donaire said.

"I told him you've just got to go in there at 100 per cent, doesn't matter who it is; don't think about the age, the experience, all his accolades, when you go in there."

Australian Associated Press