An MTA worker was hit in the face with pepper spray on Christmas morning in Harlem, cops said.

The 37-year-old victim was operating a northbound No. 2 train as it pulled into the 135th Street and Lenox Avenue station in Harlem around 3 a.m.

When she opened the train’s window, a man sprayed the substance in her face, police said. 

She was taken to Harlem Hospital with redness and swelling to her face, cops said.

The man who sprayed her ran away to the street, cops said.

He was wearing a gray sweater and blue jeans.