Police are hunting for a violent carjacker after a woman was punched and threatened with a knife at Chadstone Shopping Centre.
The woman fought off the violent attacker in an underground car park at the shopping centre last Monday.
Police have released an image of a man they would like to talk to about the incident.
The woman was near her car when a man approached her about 7.30pm, held a small knife to her face and demanded her car keys.
She quickly got into the driver's seat but the man tried to take her handbag from her shoulder.
He then punched the woman in the face and held the knife to her throat, demanding her car keys again.
The woman began to shout and beep her car horn, alerting nearby witnesses.
Two tradesmen came to the woman's aid, one chasing the offender and the other staying to help the woman.
The man fled on foot into the shopping centre.
Detective Senior Constable Briony Baird said the attacker probably thought the woman would be an easy target - until she fought back.
"We do have concerns that he's picking on people that are smaller than him, that are female," she told Nine News.
Anyone who recognises the man or has any information about the incident is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential crime report at crimestoppersvic.com.au.
- with Steve Lillebuen