Nelson Asofa-Solomona enters his November 6 Sydney bout with Paul Gallen as Sportsbet's favourite, priced at 1.68 compared with Gallen's 2.15.
The 30-year-old former NRL player has won three boxing contests by knockout, defeating Jeremy Latimore, Jarrod Wallace and George Burgess.
Gallen, who is 15 years older, dismissed the significance of those victories and argued that Asofa-Solomona has not faced a notable opponent.
"He's smashed a couple of blokes who'd never had a real fight in their life," Gallen stated.
Gallen's own record includes victories over former WBA heavyweight champion Lucas Browne, UFC figure Mark Hunt and Sonny Bill Williams.
He also lasted 10 rounds against Australia's current heavyweight contender Justis Huni before losing a competitive fight in 2021.
"But I've shared a ring with a world champion. I've out-classed guys a hundred times better than Nelson.
"Plus, I don't go in there with anything to lose. He's got everything to lose … and it's not going the way he thinks."
Asofa-Solomona, who hopes to advance his boxing career, said Gallen's previous achievements would have little bearing on fight night.
"Everyone wants to talk about my boxing IQ and experience … let's see how much that matters when I land one on his jaw," NAS said.
"I'm happy for him to keep living in the past - talking about blokes he beat years ago.
"I don't care what he did five years ago. I care about November 6.
"So enjoy the build up and all the memories, old boy. Come fight night, there'll be a new memory for everyone … sadly, you won't remember it though."