UFC middleweight Marvin Vettori challenged Jake Paul and said, "Put your nuts down on the table."
Paul has already defeated two UFC fighters, the most recent being Tyron Woodley's brutal knockout.
UFC middleweight Marvin Vettori challenged Jake Paul in a sparring match
Vettori, a 28-year-old current contender, wants a piece, even if it is behind closed doors in the gym.
Vettori tweeted Paul: "Let’s set up sparring. I will match any bet that you wish.
"You can claim anyone, any time, anywhere, but you won’t go further than 6 rounds, I promise you that.
"Put your nuts on my table, I want to feel if it's possible to really box."
Vettori has previously sparred with David Benavidez, ex-WBC boxing champ, and was 18-5-1 in his MMA career. He lost his UFC title challenge against Israel Adesanya last May.
Paul is 5-0 as a professional fighter with KOs against Youtuber 'AnEsonGib, ex-NBA player Nate Robinson (37), and retired UFC welterweight Ben Askren (37). Woodley is 39.
Free Bets: Get more than PS2,000 in NEW CUSTOMER DEALSVettori's callout comes in the midst of a social media feud between himself and Dana White, UFC president.
White agreed to test positive for cocaine over the next ten year, provided he could also test positive for steroids with Paul in the next 24 hours.
Paul retorted, "Steroid test me whenever you want. Two weeks have passed since my fight, and I'm still a fat little girl.
"And it's a compliment because I have no other excuse to knock out all your champions [than]," This kid uses steroids.
"Look at me. "Look at me, fat little girl. If you steroid-test me, I'd love to steroid-test every one of your fighters.
"Oh, but you won't do it, will you?"
