The crook was walking behind the victim when she headed up the steps to St. Demetrios Greek Orthodox Church in Briarwood about 8:20 a.m. Sunday, cops said. The holy site has a service that begins at 8:30 a.m.

Video shows the man creeping up behind her and quickly climbing the steps next to her.

He got in front of the woman and punched her in the face, sending her tumbling back down the stairs on 152nd St. near 84th Drive.

The robber snatched the woman’s purse, which contained $300 and her cell phone, credit cards and car keys, before driving off in her 2006 Nissan Altima. He has not been caught.

The woman is a member of the church and was on her way into services when the robber targeted her, according to Father Konstantinos Kalogridis, head priest at the church.

Medics rushed the victim in critical condition to New York-Presbyterian Hospital Queens.

Anyone with information is asked to call Crime Stoppers at (800) 577-TIPS. All calls will be kept confidential.