Browns Legend Joe Thomas Dominates on 'Titan Games,' The Rock Goes Wild!

Joe Thomas -- a former 325-pound NFL offensive lineman -- DOMINATED the "Titan Games" on Monday ... and now he looks like a LEGIT contender to win the whole show!!

The former Cleveland Browns left tackle has dropped 50 pounds since retiring from pro football in 2017 ... and was personally selected by The Rock to compete on the show, going up against other high level athletes.

Well, turns out ... LINEMAN ARE WAY MORE ATHLETIC THAN YOU'D THINK!!

The 35-year-old Thomas started off slow ... narrowly beating out Denver firefighter Matt Chan in the first half of the show.

But then, he TURNED IT ON ... easily vanquishing his second opponent -- Franklin County Sheriff's Deputy Steven Shelby -- on the famous "Mount Olympus" course.

Mount Olympus is no joke -- competitors have to scale walls, move heavy objects, move a giant heavy stone with a steel chain, smash a coffin with a sledgehammer and much more.

Dwayne Johnson was so impressed with Thomas, he could barely hold his emotions together -- raving about the "Ironman" like an obsessed fan!

Thomas now moves on to the next round where he'll have more high-level competition from guys like NFL star Victor Cruz, UFC star Tyron Woodley and more!