They're both scary Irish guys ... but WWE superstar Sheamus says there's no question he'd dominate Connor McGregor in a real fight because, "I can kick anybody's ass."
Sheamus would definitely have the size advantage -- he's 6'4" and 267 lbs ... while Conor's 5'9" and 145 lbs.
Still, Conor is Conor ... violent.
There's more ... since Sheamus is especially proud of his drinking ability, we asked how many Guinnesses he could take down in one sitting.
"I lose count after about 15."
DRINKING FUN FACT -- Andre the Giant once claimed he put down 117 beers in 1 night (kids, don't try this at home).