Chicago Cubs Party As They Head On To The NLCS

The beer was FLOWING in the Chicago Cubs locker room Tuesday night -- where the players (and even Theo Epstein) partied their faces off after that insane 9th inning in the NLDS!!!

The Cubbies overcame a 3-run deficit in the 9th to beat the Giants in Game 4 -- and will now advance to the NLCS to face the winner of the Dodgers/Nationals series.

Look, it ain't exactly the World Series yet ... but any time you win a playoff series, you TURN UP!!