David Haye does not believe Anthony Joshua was fully "switched on" when he suffered his stunning defeat to Andy Ruiz Jr in June - but has backed the former champion to change that in Saturday's rematch.
Joshua and Ruiz will do battle for the WBA, IBF and WBO heavyweight titles in Saudi Arabia after the Briton suffered his first defeat at Madison Square Garden in their previous meeting.
Conspiracy theories raged after the fight about why Joshua had underperformed and whether he had gone into the fight fully fit.
Former WBA heavyweight champion Haye has offered his best guess on what went wrong and thinks a different Joshua will be on show for the second bout.
"No fighter is ever 100 per cent going into a fight, you always have niggles," Haye said to the Mirror.
"When you're sparring - physically fighting - a week before you’re always going to get strains and aches, torn muscles, issues with tendons and ligaments.
"You just have to get into the ring as close to 100 per cent as you can. From the outside, it didn’t seem that Joshua was switched on 100 per cent - but that's an uneducated guess.
"I don't know that; I'm guessing because his performance wasn't that of someone who was 100 per cent, or as close to 100 per cent, as he usually is.
"But I believe he will be switched on significantly more on Saturday night compared to how he was in Madison Square Garden."
Haye feels Joshua tried to finish the fight too early having dropped him in the third round before going down a total of four times himself in a defeat that shocked the boxing world.
"What he was surprised about was when Ruiz went down heavily and Joshua went in for the kill, but he hadn't cooked him enough," added Haye.
"He hadn't broken him down before he put on the final onslaught that should have closed the show.
"Then he walked on to a mighty left hook which changed the direction of the fight."