Carl Nassib became the first openly gay player ever to play in an NFL game on Monday night ... and then he came up big for his squad -- helping the Raiders win with a huge sack in overtime!!
Lining up for the first time in a regular season game since opening up publicly about his sexuality in June ... Nassib was all over the field during Las Vegas' win over the Ravens on "Monday Night Football."
He logged three tackles and was disruptive throughout the evening -- but in the game's overtime period, he made a monster play to help lead the Raiders to a victory.