That is according to talkSPORT boxing pundit Gareth A Davies, in a big reveal the day before they run it back in Saudi Arabia at the Jeddah Superdome.
Fresh off his disappointing defeat to Usyk in their first fight, Joshua appointed Garcia as his new head coach to replace the recently departed Rob McCracken.
But Davies’ inside information will give some fans cause for concern that it won’t go according to plan for Joshua tomorrow night.
Davies told Behind The Gloves: “I’ve heard they haven’t seen eye to eye the whole time.
“It’s a new relationship. In the second relationship, you’re working through things. That’s all really good news for me. They have been working on his confidence. Change the momentum from the first fight because it was the wrong game plan to try and box Usyk.
“Be aggressive, be dirty, push him around, close down the space, let your hands go, but obviously with educated pressure. Usyk knows what Joshua is going to do. He’s going to let his hands go a bit more and be more physical with him.
“He’s not going to stand off and try and jab him and close the space in that way. Usyk is up against a formidable Adonis, who has very heavy hands, a bigger, heavier, stronger man.
“So, he’s preparing for that, and I think he’s wanting to maybe finishing the fight as well and fight fire with fire. He knows he’s got the tricky skills to do it. He needs to be strong in there.
“Maybe he doesn’t want to go 12 rounds this time. I don’t buy he’s 20 kilos heavier, but he certainly looks thicker around the torso and stronger.”
Many observers, including former world champions Carl Froch and Johnny Nelson, believe Joshua could retire if he loses on Saturday.
And Davies says he can understand exactly where they’re coming from as he feels much the same way.
He added: “Well, he might [retire]. Johnny [Nelson] is fine saying that. He’s not saying that Joshua should retire.
“What he’s saying is if he’s knocked out by Usyk and outboxed again and can’t get anywhere in the fight. He might want time to psychically, mentally, and psychologically recover.
“He might say, ‘I’ve reached my zenith, and maybe there isn’t anything bigger ahead for me. Johnny was only giving his view. Of course, he wants AJ to win. We all would love for AJ to win, but he was just being honest.”