Justin Bieber -- BREAKS SCOOTER'S ANKLES ... In Quasi-Impressive Basketball Clip

Here's Justin Bieber playing basketball again ... decently ... only to be overshadowed by the incredible acting performance of his flop-happy manager Scooter Braun.

Bieber and Scooter were playing some 1-on-1 ... when Bieber broke out his bag of dribbling tricks and pulled an "And 1" move on the guy.

Scooter, stealing a move from the Washington Generals, threw himself on his ass ... in an effort to make it seem like he got crossed over in a big way.