Garcia replaced Rob McCracken earlier this year as Joshua’s head coach for his rematch with Usyk in Saudi Arabia on August 20.
The British superstar is looking to rebound against Usyk after being beaten by him previously at the Tottenham Hotspur last September, which was the second defeat of his professional career.
With Joshua (24-2, 22 KOs) having four inches in reach over Usyk, Garcia thinks AJ’s size and strength gives him an advantage going into the rematch.
Speaking to Sky Sports, he said: “These last few days have been very positive from what I’ve been hearing from AJ not necessarily to me but to everybody around camp.
“We’ll be having breakfast together or lunch together and they tell me what he’s been saying and what he’s been talking about and the only thing in his mind is he’s going to win by knockout.
“Can he win by decision? Yes. I know that he can also win by decision because if he controls the fight with his long punches, using a lot of jabs, even though we want him to back him up, but if he just uses the reach and that half distance where he’s controlling the fight, he could easily win a decision too.
“But, does he have the power, does he have the strength, has Usyk been dropped before? Yes. Does he like body shots? Probably not because he’s been dropped a few times with body shots.
“Can he knock him out? I think so. And that’s what we’re going for.
“I think Anthony knows it himself, and myself and Angel Fernandez, we’re going to push him to go for the knockout.”
But in terms of wins he insists that this one will be the best of the lot.
He continued: “I’ve had great wins but this would be the best win of my career as a trainer.
“Just the fact I’m training a former heavyweight champion of the world, that’s already a big accomplishment.
“But winning the title, you know, very few trainers can say that they trained a heavyweight fighter to become the champion of the world, and that’s the one thing that I was always looking forward to one day you know.
“I’ve trained a few heavyweights, but never to championship level, you know. And yes, most of my champions have all been maybe from welterweight and under. There was a lot of talk of ‘well, he’s never worked with heavyweights’, but I don’t think there’s much of a difference.
“If a fighter is listening to his trainer, if a fighter believes in his trainer and he follows instructions, there’s no difference.”