A 13-year-old was in critical condition after falling off his bicycle and being mowed down by a hit-and-run SUV driver in Bensonhurst, law-enforcement sources said.

Police weren’t sure whether the driver was aware he had left the boy bloodied on 20th Avenue near 80th Street at around 3:40 p.m., yesterday when he continued north.

Horrified onlookers ran to the victim’s side to comfort him.

The teen, whose name has not been released, was rushed to Coney Island Hospital.