A 57-year-old Preston man is fighting for life in hospital following an alleged hit-run at the intersection of Spring and Edwardes Streets, Reservoir about 9.50pm.
The Preston man was crossing the road when he was struck by a car. Police allege the driver then fled the scene.
Protective Service Officers on duty at Reservoir railway station witnessed the incident and rendered assistance to the victim.
He was taken to hospital with life-threatening injuries.
About 30 minutes after the incident, the alleged driver returned to the scene and was arrested by police.
A 26-year-old Thomastown man remains in custody and will be interviewed by investigators today.