Paul, 26, is coming off the back of a ten-round points win over ex-UFC star Diaz, 38, in August.

And both the American and the PFL have proposed a rematch in the cage and offered up to £10million.

But Diaz has seemed uninterested and Brown insisted he has reason to.

He told MMAFighting: “Jake Paul, I’m going to pick him to win. I’m going to pick him to beat Nate Diaz in MMA.

“We already know he can outbox him. When was the last time you saw Nate Diaz take someone down?

“But I don’t think he’ll be able to take him down, even if he tries to [take him down].

“He’s way, way undersized. Jake Paul is so much bigger than him. I don’t know what weight it will be at, probably 185.

“Nate’s not a great wrestler, it’s going to end up staying on the feet. What difference would it be [from their boxing match] if it stays on the feet?”

Ex-high school wrestler Paul has called to fight Diaz in his MMA debut and Brown believes the styles clash favours the American well.

He said: “First, Nate rarely throws elbows. Really doesn’t throw kicks a whole lot. He’s primarily an MMA boxer.

“His MMA style is he pressures you, he outboxes you and pressures you until you take him down or grab hold of him, which, that’s what he wants. Now he can do his jiu-jitsu game. It’s just a bad matchup.

“I wouldn’t pick very many people to be able to do that, but I don’t think Nate will be able to take [Paul] down and we already know what’s going to happen on the feet.

“Jake will train for kicks and elbows and knees and all that stuff and they might have a little effect.

“But I don’t see Nate finishing him with a kick or even really chopping him down or elbowing him. It’s just not his style.”

Matt Brown backed Jake Paul to beat Nate Diaz in MMACredit: Getty