A gutsy teen fought back against her subway sex assaulter and snapped a photo of him before fleeing a Brooklyn train, police said on Wednesday.

The 15-year-old girl was riding a northbound D train in Gravesend on Friday around 3:30 p.m. when the stranger walked up to her, touched her inner thigh and tried to kiss her, police said.

The girl shoved him onto the floor, police said.

She snapped a photo of her attacker, who was possibly drunk, and fled to a different train car.

Cops describe the creep as 35 to 45 years old, 5-foot-3 to 5-foot-5 tall and 160 to 180 pounds.