Masvidal, 35, was watching on from ringside as the YouTuber scored an emphatic knockout in Florida on Saturday night.
The 24-year-old stopped Tyron Woodley in the sixth round of their hastily-scheduled rematch at the Amalie Arena in Tampa Bay.
Paul first of all fixed Woodley squarely in his sights before a booming right hand sent the 39-year-old crashing to the canvas.
The bout had been a fairly dull affair up until that point, with Woodley seemingly hesitant to pull the trigger.
Masvidal then left in disgust before the final result was read out, which Paul took exception to in his post-fight interview.
“Masvidal and Nate Diaz – y’all [sic] are b—– for leaving this arena, because I know you don’t want that s—,” Paul said after the fight.
“So get out of your contract with daddy Dana [White] and I will f— you up too.”
And Masvidal has responded by uploading a video of himself on Sunday morning to issue a chilling threat.
In it, Masvidal said: “Now to address that little b—-, that f—–.
“Listen man, you can’t f—— afford me. Me and the other names that you mentioned, you can’t afford. I know what you pay.
“You talk a big game. You say $50 million here, $100 million there, but b——-. If that was the case, [Floyd] Mayweather would have took the f—— fight with your b—- ass, but he hasn’t because you don’t generate that type of revenue.
“You’re giving out free tickets. You’ve got street teams giving out free tickets. Who the f*ck are you selling dreams to? You can’t afford me to come over [to boxing].”
Before cutting one of the best promos in recent memory, “So let me tell you a little secret about me you didn’t know: I fight for money or to fight the best in the world. You’re neither.
“You understand? I know it hurts, but you’re neither the best in the world or make me money.
He continued, “I tell you what, come on over to the UFC, sign a one-fight deal, let Dana [White] give whatever the f— he’s got to pay you, I’ll break your jaw in front of the whole world. I promise you that.
“If you really want it, come get it. Man to man s—. None of that boxing s— where I can’t slam you on your spinal cord and leave you in a wheelchair for life.
“No, come on over so we can do everything. If you want it, it’s here. If not, shut the f— up.”
WATCH: UFC star Jorge Masvidal has made a chilling threat to Jake Paul
Check out the video below…