Justin Bieber — Ringside for BFF’s Boxing Debut … Lil Za Wins!!!!

Ringside for BFF’s Boxing Debut … Lil Za Wins!!

EXCLUSIVE

Justin Bieber was part of ANOTHER boxing entourage last night … to watch his BFF Lil Za get in the ring during a the high classes fight night in Los Angeles … and TMZ Sports has the footage.

Bieber — who’s usually in Floyd Mayweather’s corner — sat in the front row and held up a sign saying, “WE…