Man critical after being flung into the air by car crossing Sydney road

An unsuspecting pedestrian remains in a serious condition in hospital after he was hit by a car while he crossed the road in Sydney.

CCTV shows the 32-year-old walking across the intersection of Cleveland Street and Abercrombie Street in Darlington about 4.30pm yesterday before being collected by a Mitsubishi Lancer.

In a stroke of luck; an ambulance was on scene within 40 seconds of the incident.

"We had a car that just happened to be in the area, they didn't receive a triple-zero call at that stage they were just driving past," paramedic Giles Buchanan told 9News.

The man was taken to Royal Prince Alfred Hospital in a critical condition, suffering a fractured skull. He remains in the intensive care unit.

A 19-year-old man, driving the Lancer, was uninjured in the crash.

Police are investigating who was at fault.