A cop rear-ended an SUV so hard on Staten Island that it flipped over, police said Monday.

The police officer was driving north on the shoulder of the West Shore Expressway near Victory Boulevard around 4:30 p.m. Saturday — his lights and sirens going as he responded to a call of an unconscious child in a car — when a 71-year-old man pulled his Lincoln SUV onto the shoulder in front of the cruiser, authorities said.

The impact of the cruiser slamming into the SUV flipped the black Lincoln over onto its roof, cops said.

Both the 71-year-old man and the cop were taken to Staten Island University Hospital in stable condition.