The Queenslander, who famously scored a stunning unanimous points decision over Manny Pacquiao in July, faces the undefeated Crawford (32-0-0) in Las Vegas on June 6, and Arum is already considering what a victory would mean for the 30-year-old former schoolteacher.

"If Horn wins it's a tremendous victory for him. He becomes the boss," Arum said in response to questions from Horn's promoter Dean Lonergan. "He remains the welterweight champion and he goes into the records in boxing as one of the most elite fighters in the sport."

While there is plenty at stake, most boxing analysts and pundits are expecting Crawford, who is widely considered one of the world's best pound-for-pound fighters, to make light work of Horn.

Arum, however, remains split on the outcome of the fight and believes you'd be a fool to write off the gutsy Australian this early, particularly given his recent history.

"If you talk about boxing skills there's no question they belong to Crawford but when you talk about size, strength and determination you have to give Horn a very good chance," Arum said. "I don't know who will win this fight, a lot will depend on the determination of the two boxers.

"All I know is that it will be a good, hard fought competitive match. The winner of this fight will be considered the big superstar of the welterweight division."

Jeff Horn and Ray Robinson pose for a photo before their sparring session at Stretton Boxing Club. Bradley Kanaris/Getty Images

Should Horn pull off the upset win, it would open further doors and the possibility of another title fight in his native Australia remains a real possibility.

Currently there is no rematch clause in the Horn-Crawford fight contract, but Arum believes the American would certainly consider a second fight.

"If it's a great fight and Horn wins and agrees to fight Crawford in a rematch in Australia I'm sure Crawford would be amenable to that," Arum said. "[If Horn wins] a lot of elite fighters like Pacquiao and others will be knocking on his door looking to challenge him."