Rob Gronkowski tried spitting bars (again) -- this time in rap battle form -- and got absolutely WRECKED by "Jane the Virgin" star Gina Rodriguez.
On "Drop the Mic" ... Gronk took the stage in a tank n' chain, bragged about his Super Bowl rings and dropped some cringy sex jokes on Gina.
"You're a Virgin, I'm not -- I score all the time."
Gina responded with a series of shots at Gronk's intelligence ... leaving the Patriots superstar looking legitimately hurt.
"I spit fire -- you look like the caveman that discovered it.