An overzealous Phillies fan learned the hard way he should've just celebrated his team's NLCS win from his seat Tuesday night ... 'cause when he tried to race onto the field to cheer on his squad, he got LEVELED by a security guard.
The man's ill-advised jaunt in the outfield of Citizens Bank Park happened just seconds after Philadelphia put the finishing touches on its 10-0, Game 2 victory over the Arizona Diamondbacks.
You can see in video shot by a fan at the game .