TMZ Sports reported that Diaz apologized to the man, saying he didn’t want trouble — and then three other guys joined in against Diaz and things got physical.

“I didn’t start it,” Diaz told TMZ Sports afterward. “They didn’t know who I was.”

Diaz attempted to defend himself, TMZ said — but when he got hit hard on the head, all bets apparently were off, as the brawl exited the bathroom and hit the Bellagio casino floor.

A club rep told TMZ the attackers were swinging chairs and were clearly the aggressors — but Diaz reportedly dispatched them all quickly, taking them to the ground and using choke holds on the men.

Diaz was asked by the club if he wanted to press charges, but Diaz told TMZ that wasn’t necessary: “They got the worst of it.”

(H/T: IJR)