The car was travelling on Parker Road in Silvan, east of Melbourne, when it lost control on a bend at about 6.30pm yesterday.
The car hit a tree and burst into flames, trapping the driver in his seat.
An off-duty Victoria Police detective sergeant who was driving past, and a local woman who heard the crash, came to the man’s aid.
They were able to free him from the car and get him away from the flames.
The woman received burns and was taken to hospital.
The driver, a man believed to be in his 50s, was airlifted to hospital in a serious condition.
Police are investigating.