Garcia (36-0, 30KOs) is the reigning WBC world lightweight champion, but is stepping up to 140lbs to face Broner in a catchweight contest with no titles on the line.
Already regarded as one of the best current pound-for-pound fighters, this promises to be a tough examination for California native Garcia, 29, against a former four-weight world champion who is naturally the bigger of the two.
"I think he will be the toughest challenge, the toughest opponent, the most accomplished fighter, that I have faced," admitted Garcia.
"So, honestly, I think it will be the toughest fight of my career so far. I've been faced with some guys that are supposed to be heavy punchers, but I haven't felt their power. I have the right game plan and didn't really feel it.
"Dejan [Zlaticanin] was supposed to be a big power puncher; I didn't feel it. [Orlando] Salido is a heavy hitter. He has become champion even after I beat him. He still became champion several times and beat some tough guys. And I didn't feel his power.
"But I think Adrien Broner is the guy that probably hits the hardest out of everybody - especially because we're moving up in weight. He is a bigger man naturally than me as far as weight is concerned.
"I haven't had a challenger, you know, really push me to the next level. And I think Adrien Broner will do that. And I'll be able to show everybody, you know, another set of Mikey Garcia you still haven't seen."
Garcia insists he wants to move back down to lightweight (135lbs) at some stage after the Broner fight, but has not ruled out the possibility of staying at 140 or even going up to 147lbs.
"I still have plans on coming down to 135 to unify the titles or have a big title defence," he said.
"But, you know, after being in boxing so long and learning the policies on the business about it, you got to be flexible. You got to be able to adjust and make those adjustments and continue with my career.
"I'm not going to sit around, wait for a fight, you know, and chase anybody. I'm here to take on the biggest fights available, the biggest challenge available, whether that means at 135 or at 140 or possibly even 147.
Garcia insists putting on the extra weight has not been a problem for him as he prepares to enter the ring the heaviest he has been as a professional.
"The camp has been great. As far as the weight, that's never been a problem and it's just training hard, you know, getting in shape," he said.
"That's the number one thing. The weight is not actually a problem and I'm not worried about it. We just actually are eating a little bit more than usual to keep the weight higher because I would have dropped weight too soon and we're sparring big guys and we don't want to do that.
"You know, it's not the correct thing to do. So I just feel very comfortable right now."
