Former world champion Anthony Mundine has laid bare the enormous challenge confronting George Kambosos Jr on Sunday, lauding American challenger Devin Haney as a "masterclass" of international boxing.
Kambosos will place his WBO, WBA and IBF belts on the line at Marvel Stadium in a bid to capture Haney's WBC strap and become the undisputed lightweight champion of the world.
Just 23, Haney's record stands at 27-0 (15KO) after leaving the amateur ranks as a 17-year-old.
While at his career peak, Mundine sparred with a young Kambosos and was impressed by his intensity and speed.
But he said Haney was a "cool cat" who brought plenty to the table.
Little wonder Mundine can't split the two undefeated combatants and says Kambosos's game plan will be critical.
"I'm an avid boxing fan and I know a lot of the young talent coming through," Mundine told AAP.
"Devin is definitely one of the masterclass of boxers out there in the world today, especially in the lightweight division.
"I think it's a 50-50 fight and the one who has the upper hand is the one who is the most effective with their game plan on Sunday.
"That's why it's so intriguing."
Haney's trainer father Bill was denied a visa into Australia and Mundine, who was trained by his own boxer father Tony, could sympathise.
"It may affect Haney and if I was in that situation it would play some part," Mundine said.
"But it wouldn't take away my mindset and my focus on what I needed to do in order to get the victory."
But legendary trainer Johnny Lewis disagrees, insisting Haney not having "the trust" of his father in his corner could swing the bout Kambosos's way.
"It's a massive loss to him," Lewis told AAP.
"I'm sure if young George didn't have his dad over there, he'd feel the effects of that and the same way Haney will miss his father.
"Of course he can overcome it. He's a world-class boxer and has never been beat but I think he'd like to know he could come back after each round and have his father there."
Haney will instead have Zab Judah's trainer father Yoel in his corner, 21 years after Judah's camp claimed he'd been robbed in a second-round knockout that allowed Kostya Tszyu to unify the light-welterweight division in Las Vegas.
Lewis was Tszyu's trainer that night and says the Judah camp feeling hard done by all these years later spells trouble for Haney.
"The referee saved his life. He (Judah) was gone," Lewis recalled on Friday.
"He couldn't have taken those punches that Kostya was going to throw at him. He would have bombarded him. He didn't know where he was.
"If that's what he's got in his corner, then Haney will be shitting himself.
"If he sent Haney out like that, well then I'd be very worried if he was in my corner."