The 32-year-old star was comprehensively defeated by Usyk in their first fight, and Tony Bellew - who lost to Usyk in 2018 - acknowledges that the Brit has a huge challenge on his hands in their rematch in August.
He told DAZN: "Since the loss to Usyk, Joshua has made huge changes to his team with Angel Fernandez taking a bigger role and the legendary Robert Garcia also coming onboard.
"All eyes will be on Robert Garcia in the build-up to this fight and it’ll be interesting to see what changes he can make to Joshua at this stage of his career.
"He was a winner as a fighter, he’s a winner as a trainer, and he’ll be fully focused on winning when preparing Joshua for the biggest test of his career."
Joshua was widely criticised for his cautious approach in their first fight.
But this time, Bellew thinks he's adopt different tactics.
He said: "If Joshua can use his size, speed, and power, but do it correctly, then he can get Usyk’s attention and let him know he’s in with a different animal from the first fight.
"That’s the approach Joshua should take. Let Usyk know he’s in a tough fight right from the outset."
Joshua recently signed a money-spinning TV deal with DAZN, and Bellew believes he'll remain a prominent feature in the heavyweight division even if he loses the rematch.
The former world champion said: "This fight will mean the world to Joshua after what happened in the first one but make no mistake about it, he’s going to be a threat in this division no matter what the result.
"If he can’t get past Usyk then he might have to put his world title dreams on hold for a little while but that doesn’t mean that the climb back to the top won’t be eventful."