An East Village man raced to his girlfriend’s rescue Monday night, stabbing another man — her mom’s boyfriend — in the face when he walked in on him strangling her, police and law-enforcement sources said.

The messy domestic dispute played out in a 12th-floor apartment in the Jacob Riis Houses around 11:30 p.m. when Eugene Turner allegedly throttled his girlfriend’s adult daughter, police said.

The daughter’s enraged boyfriend ran in and knifed Turner, 39, in the jaw and lip before dashing out of the Avenue D building, cops said.

Turner was taken to Bellevue Hospital for non-life-threatening injuries — and charged with strangulation and assault with intent to cause physical harm, police said.

The woman was not seriously injured.

The stabber remained at large Tuesday afternoon.