Not even a 29-point loss to his former team could stop James Harden from getting in some quality time with Travis Scott, Meek Mill and Lil Baby ... 'cause the Sixers superstar went out with the his rapper friends right after the game.
The Beard had a less-than-stellar performance against the Brooklyn Nets on Thursday ... scoring 11 points and going 3-17 from the field.
But, the bad night only lasted on the hardwood, 'cause the 32-year-old was spotted out celebrating a friend's birthday out in NYC at Sei Less restaurant shortly after the L ... and everyone was all smiles.
The trio of bros were spotted singing and cheering as cake with sparklers was delivered to their friend.
La Flame and Lil Baby were also courtside for the lopsided contest at the Wells Fargo Center ... but appeared to be in great spirits nonetheless.