ANTHONY JOSHUA brutally shut Francis Ngannou down following a boast about flooring Tyson Fury.
AJ faces the ex-UFC champion on March 8 in what will be only Ngannou's second professional boxing bout.
In his debut in October, he astonishingly floored Fury but it was not enough to avoid a controversial split-decision loss.
Ngannou still takes confidence from the performance and knockdown - which he doubts Joshua would have come back from.
He said in a face to face: “Yeah, I have a doubt about that. Tyson showed that he’s very resilient.
"I saw him come back from a knockdown that you wouldn’t believe.
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"So I think he’s probably one of the most resistant person out there, and that’s not a disrespect to AJ.
"I don’t believe that AJ would take what Tyson did.”
But Joshua - with a stoic glare - hit back at Ngannou: "Who hasn't knocked Tyson down? So many people have knocked Tyson down."
Fury, 35, has been floored seven times in his career but bounced back to his feet every time to remain undefeated.
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Joshua was due to face Deontay Wilder, 38, in March but the deal went up in smoke after the American's shock loss to Joseph Parker.
And Ngannou, 37, was denied a rematch with Fury, who instead moved on to an undisputed fight with Oleksandr Usyk, now set for May 18.
So Saudi boxing chiefs acted fast to match the giant heavyweight pair together for another crossover clash in Riyadh.
Joshua, 34, said: “They spoke about this fight before and I said ‘no, it’s a gimmick fight, it’s not something that I think is right — crossing over when I’m still chasing heavyweight glory’.
“And then I think when they saw what happened with his last fight, the situation with Wilder, this opportunity presented itself.
"I never turned down a challenge and I’m looking forward to it.”