A 76-year-old Brooklyn woman was punched in the back of the head by a stranger in what residents fear could be the city's tenth "knockout game" attack.

The woman fell to the ground after being punched, as a rally was wrapping up that was held to protest the recent “knockout game” attacks.

She was treated at local hospital and discharged, but police are still searching for her attacker.

 The "knockout game" has already reportedly claimed lives in SyracuseSt. Louis and New Jersey.