Horn has nailed the 'free of admirers' part since he arrived in Nevada, where his lengthy battle to earn the respect of US fight fans and much of the media has continued.

The sports book at the MGM Grand, where the fight will take place, has him as a 10-1 outsider to roll the 32-0 Crawford, who ESPN and promoters Top Rank are desperate to become the next American boxing superstar.

During the week, Crawford went on the radio show of ESPN's Stephen A Smith, one of the most-vocal critics of Horn's win over Manny Pacquiao. One of his questions was: "I'm just going to assume you are going to take care of this brother Jeff Horn ... who's next on your hit list?"

Through it all, Horn's iron will to not only compete with Crawford but put him on his back has only intensified. The invisible combatant in a two-horse race, he understands the only antidote to ongoing derision is prime-time success.

“America is one of the biggest countries in the world. They’re very innovative with what they’ve done in the past, they are in their own little world over here because they’ve done so much as a nation," Horn said.

“They ignore everything that happens on the outside but we’re always here to make surprises, from little old Australia that supposedly doesn’t exist. We’re here to shake it up a little bit."

With Mexicans and Brits and Ukrainians now among the biggest names in the sport, America is desperate for a new boxing darling. Crawford has been chiselled in as that man, perhaps somewhat reluctantly given his introverted nature and often clunky dealings with the media.

Yet not everyone has flushed Horn's chances down the toilet just yet, least of all the fighter himself, who believes wholeheartedly that he will stun the fight world once again when the bell rings.

Horn is a simple man but difficult to stereotype in a sport where badder is often perceived as better. He doesn't look, or even act, like a fighter, so the pieces don't neatly fit. Yet on Saturday night, a goofy ex-teacher from the Brisbane suburbs will try to tear the meanest man in boxing to shreds.

"The dichotomy of his mindset and demeanour is so stark that he's somehow humble, genuine and irrationally confident at the same time," wrote CBS's Brian Campbell in one of the few sympathetic pieces towards Horn in the local media.

Outside of the Horn camp, perhaps the most confident man in Las Vegas is matchmaker Stuart Duncan, who has been instrumental in plotting the path for Horn to the point where he will headline in Vegas against a Hall of Famer after just 19 fights.

And it's not just Horn's ability that has been sold well short of market worth. Duncan also sees his trainer Glenn Rushton as somewhat of an eccentric boxing savant.

"Jeff's got an x-factor about him. He's a lot stronger than what he looks, he hits a lot harder than he looks," Duncan said.

"I've worked with a lot of world-class coaches over a long period of time. Tactically, [Rushton] is one of the best. He's seriously good."

Duncan hand-picked all of Horn's opponents but had no say in this fight as Crawford was installed as a 147-pound mandatory after vacating his suite of belts at 140 pounds.

He knows how good Crawford is but he's yet to find out how high Horn can rise. He's managed to lift on every occasion, Duncan said, so there's no reason why Saturday (Sunday, 12,30pm AEST) won't be a repeat.

"This is a tough fight. A very, very, very tough fight. The harder the opponent we put in front of him, the better he fights," Duncan said.

"Taking nothing away from Jeff's ability but have a look at the performance he put in against Manny Pacquiao compared to the performance he put in [in a voluntary title defence] against Gary Corcoran.

"It was a very distracted lead-up but he pulled it off no problem at all. I think you will see a very different Jeff Horn, see a better Jeff Horn than the one that faced Pacquiao.

"We had no say [in the opponent] but I can say no stone has been left unturned in getting him ready for this fight."

Experts have almost universally tipped Crawford to not only win but dominate. Duncan sees things very differently.

"I believe Jeff can grind him down by round six or round seven. Would I tell my family to go and put money on that? No. But that's my gut feel. I spend a lot of time studying styles. I do believe he can get it between six and seven. I really believe he can do it."