Roman Reigns Vows To Crush CM Punk At WrestleMania, But Can't Let Emotions Take Over

Roman Reigns is training 'round the clock ahead of his showdown with CM Punk at WrestleMania 42 ... and while he's ready to crush "The Best in the World" in Vegas -- he says there's one thing that could come between him and the Heavyweight Championship.

His emotions.

The "Original Tribal Chief" was leaving Del Frisco's in NYC this week ... when Adam Glyn asked how he's staying in tip-top shape weeks before stepping foot on "The Grandest Stage of Them All" -- and he admitted his regimen "sucks."

RR broke it all down ... revealing he does three-a-days and meal prepping with no cheat meals whatsoever. In fact, his order at the steakhouse wasn't a cheat meal at all, as he still had his health as a priority.

So when it comes to Punk, it'll be his 11th Mania main event ... and he said they just keep getting bigger and bigger.

While he's got the edge in athleticism, Reigns credits Punk for being a top competitor ... meaning he has to be on his Ps and Qs.

"I have to make sure that I have all my ducks aligned, I'm focused. Because when I get a little bit emotional, I take my eye off the ball, I can miss," Reigns said.

"If I do everything right, he doesn't have a chance, but he's good at making people make mistakes."

Reigns last held the championship in 2024 ... when he fell to Cody Rhodes.

As for his acting career, Reigns said he's doing a good job balancing it with WWE ... and there are a lot of good gigs that are gaining his interest.

There's been some chatter about his time on set for "Street Fighter" -- Rhodes, his costar in the flick, claimed the two were forced to keep a distance off camera ... but Roman said it was the "American Nightmare" who requested the separation due to nerves.