If you thought Jon Jones and Daniel Cormier had bad blood ... you're right.
But, also, Marvin Vettori and Israel Adesanya CAN'T STAND EACH OTHER -- and Marvin tells TMZ Sports he can't wait to punch the guy in the face this weekend!
"There's nobody that I would like to beat up more and I get to do it Saturday night," the 27-year-old Italian tells us.
"At the end of the day, I'm happy, I get to beat his ass and get his belt."
The two are clashing at UFC 263 in Glendale, Arizona -- a rematch of their 2018 fight, which Adesanya won by split decision.
But, this time, there's more at stake -- Izzy is the reigning UFC middleweight champ ... and Marvin is OBSESSED with taking his belt.
"I'll stop him with punches," Marvin says ... "I'm coming to get the belt. Keep it tight for now because it's not gonna be long until I get it."
Marvin was also tapped for an endorsement deal with Dolce & Gabbana -- and says he's looking to make them proud on Saturday!