9/4 -- Norman's attorney, David Diamond, tells us his client was the one who was attacked that night at the club. Diamond says 3 men (including the one injured) went after Norman, but Norman did not fight back, he only stayed in a defensive stance until security intervened.

Diamond continues, "My client voluntarily went to give his statement to law enforcement and no charges have been filed. The security footage coupled with the witness statements will show that my client is clearly and without any doubt, innocent."

Mick Jagger's daughter is allegedly dating a VERY violent man ... 'cause he got busted for punching the hell outta another man so badly he needed brain surgery.

Law enforcement sources tell TMZ ... Georgia May Jagger's BF, Norman Theuerkorn, was at the Blind Dragon in WeHo last month when he approached 2 random men and said he was a famous actor. He's actually a model with the Two MGMT modeling agency. One of the guys is Andrew Knight, who claims to be Suge Knight's son. The other is Andrew's BF, Darren Young.

Cops say Norman touched Darren's leg and told him he was beautiful. Both Andrew and Darren were not amused and told Norman to scram.

About 20 minutes later, our sources say Norman returned and punched Darren so hard in the head, he fell and suffered a nasty gash on his head that led to internal bleeding and, ultimately, brain surgery.