Ronda Rousey's first wrestling match wasn't just great, it was the GREATEST OF ALL TIME -- so says WWE Hall of Famer Jim Ross.
Good ol' JR was at WrestleMania 34 to watch Ronda take on Stephanie McMahon and Triple H up close and personal ... and told us he's never seen anyone dominate the squared circle this fast.
"I thought Ronda Rousey's debut was the most impressive thing I've seen in pro wrestling in my 40-year career ... best debut I ever saw," JR told TMZ Sports.
JR also gave WWE mad props for pickin' up the UFC mega-star -- calling it the 2nd best hire they've ever made besides him (lol), and saying she's a "huge star" for the company.
As for Ronda ... she's been poppin' up on "Monday Night Raw" since her match at 'Mania, kickin' ass and takin' names arms.