LeBron James Sits Courtside with Bottle of Tequila at NBA Finals

LeBron James isn't playing in the NBA Finals, but he's definitely playing AT them ... as he was spotted chilling courtside in Phoenix ... with a full bottle of Tequila!!! Hardcore playing.

King James was quite the sight Saturday night during Game 5 -- he had the bottle of booze between his legs, sitting on the court. Fans know LeBron typically gets his way on the court, but this seemed ridiculous. Ever try bringing your own liquor into a game? Don't.

Of course, if you're LeBron it's a different story, and the bottle of Lobos 1707 was more for business than drunken fun, we're guessing.

As we've reported ... LBJ and several other NBA players are investors in the brand. There's a reason the Lakers star had the label out toward cameras. Smart business, man.

His teammate Anthony Davis and Warriors star Draymond Green are also investors in the booze.

LeBron's pal, Chris Paul, and the Phoenix Suns lost the game and now trail 3-2 in the series -- but LeBron came out the winner off the court.

And yeah, he probably enjoyed a shot or 2 himself to celebrate "Space Jam: A New Legacy" hitting theaters.