Basketball bad boy Matt Barnes was arraigned Friday on assault charges for a brawl at a Chelsea nightclub — and as he entered the courthouse, a summons server handed him papers for a related civil suit.

Barnes, 36, wearing a slick gray suit and suede shoes, ascended the courthouse stairs as the server shoved the papers in front of him and declared, “You’ve been served.”

The 6-foot-7 forward refused to accept the summons, letting the documentation flutter to the ground as he walked into Manhattan Criminal Court.

Barnes, who was just acquired by the juggernaut Golden State Warriors — who play the Knicks on Sunday at Madison Square Garden — was arraigned on third-degree assault and obstruction of breathing raps for allegedly choking a woman during the melee and slugging her boyfriend at nightspot Avenue on Dec. 5.

The hoops hothead is accused of strangling Jasmine Besiso, 26, then knocking Myrone Powell, 35, to the ground and repeatedly punching him after he came to her aid, court papers charge.

In a Manhattan federal lawsuit filed two days after the attack, the couple claims that Barnes’ hulking NBA pal DeMarcus Cousins, recently traded to the New Orleans Pelicans, also pounced on Powell, who suffered two black eyes.

Defense lawyer Alex Spiro told the judge that the alleged victims started the fight. “The complainant and their companions, we have reason to believe, were intoxicated, using substances, and that they were the initial aggressors,” he said.

He asked prosecutors to turn over any evidence related to the couple’s “motives for pursuing this case — financial or otherwise.”

Judge Herbert Moses asked Spiro if his client could return to court in mid-June.

Spiro quipped that Barnes might be unavailable.

“I have reason to believe my client will be playing in the NBA Finals,” he said.

“Good luck,” the judge said before giving Barnes a June 27 return date.

Barnes, who was released without bail, declined to answer questions as he stepped into a black SUV.