Giancarlo Stanton Bench Presses Adriana Lima In Insane Workout Video

Talk about the ultimate flex ... Giancarlo Stanton showed off ALL of his muscles in front of smokin' hot model Adriana Lima -- BY BENCH PRESSING HER!!!

The video of the Yankees superstar in the gym is insane ... he laid down on his back, grabbed Lima by the legs and the armpit -- and benched her AT LEAST 4 times!!!

It's unclear why a normal barbell and plates weren't enough for the outfielder ... but Lima sure seemed to dig it -- the supermodel was smiling the whole time!!

Of course, the feat ain't exactly tough for Stanton ... he's known as the strongest guy in the league -- so benchin' a former Victoria's Secret model was clearly NBD.

But, just to prove the guy could still lift some serious weights ... he showed off his skills with a hammer and a tire -- and yeah, dude's got the muscles!!