Anthony Joshua has been told all of his past achievements will prove "irrelevant" if he cannot set the record straight by defeating Andy Ruiz Jr in their rematch on Saturday.
His promoter Eddie Hearn described himself as "petrified" before a bout that could prove pivotal in resurrecting the Briton's career.
In a stunning defeat in June, Joshua lost his WBA, WBO and IBF heavyweight titles to late unheralded replacement Ruiz on his Madison Square Garden debut.
Joshua will seek to reclaim the belts at Diriyah Arena in Saudi Arabia, a win that should open up opportunities against the likes of Deontay Wilder and Tyson Fury in the years ahead.
A worried Hearn is all too aware of the stakes and urged his man to seize the opportunity.
"This is it, this is a moment in history, and people keep saying to me, 'Are you nervous?' I say nervous, I'm petrified," Hearn said to Sky Sports.
"But I wouldn't want it any other way. This is it, this is make or break.
"This is a moment in history for the sport of boxing and for Anthony Joshua.
"All of the past, the Olympic gold, the world heavyweight championship, the unification against Wladimir Klitschko, the unification against Joseph Parker, it's all irrelevant.
"On Saturday night, he can reclaim those titles and become a two-time heavyweight champion of the world. AJ, let's make history out here and bring them home.
"Just one job, beat Andy Ruiz, and I tell you what, if Andy beats him, there's going to be scenes at the Diriyah Arena."
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