Brandy came to support her brother Ray J ahead of his boxing match ... but Adrien Broner nearly turned her quick hello into the opening bout.

The clip shows Brandy walking into the kitchen and acknowledging Broner before moving along to greet everyone else ... but the boxer apparently wanted a warmer welcome, telling the room, "She just walked past me, but it’s alright."

Brandy immediately doubles back and corrects him ... saying, "I didn’t walk past you. I spoke to you" ... but Broner keeps the awkward moment alive while repeatedly insisting everything is fine.

It clearly wasn’t. Brandy eventually says the energy in the room is "interesting" and announces she’s heading back to her car.

That's when streamer DeenTheGreat steps in and checks Broner for being disrespectful ... telling the boxer his behavior "gotta stop" as the two begin going back and forth.

People online were firmly in Brandy's corner ... arguing Broner manufactured disrespect where none existed and blaming Ray J for putting his sister in the middle of the chaotic stream.

The encounter happened before Ray J defeated Orlando Brown by unanimous decision Saturday night at Atlanta's State Farm Arena.

Ray J handled his business in the ring ... while Brandy wisely declined a spot on the unscheduled undercard.