Knife-wielding thugs slashed a driver across the fingers and held a blade to his throat in an attempt to hijack his red Alfa Romeo.
The 18-year-old victim required surgery and police are now offering a £500 reward for information that could lead to the capture of the three-man gang.
The thugs struck at around 9pm on Saturday as the driver parked near to the Lucky Chip Shop in Rydal Crescent, Walkden.
He was about to get out of the car withthree friends when the gang approached them.
One of the raiders stuck his head through the driver's window and held a large kitchen knife to the driver's throat.
He demanded the keys and told the driveer to get out of the car - but he refused.
Instead he put his arm up to protect himself and was sliced across his hand, suffering severe cuts to his fingers.
One of the knifeman's accomplices grabbed the keys from the ignition, but the friends of the driver, who was bleeding badly, pleaded for their return so they could take him hospital.
The gang then threw the keys into the back of the car before fleeing.
The victim, who has not been named, was taken to Hope Hospital and later transferred to Wythenshawe Hospital for microsurgery.
Detective Chief Inspector John Piekos, from Salford CID, said: "It concerns me that there are still people out there determined to commit such violent robberies.
"We are determined to put a stop to this type of crime, but we need the public's support in doing this.
"That's why we're offering a £500 reward leading to the arrest and conviction of the people responsible."
He added: "These dangerous people must be stopped and taken off our streets. Their behaviour is completely unacceptable."
The attacker with the knife is white, aged 20 to 22, and 5ft 9in tall of stocky build with a bald head and a chubby, round face. He was wearing a distinctive black Gortex coat.
The other two offenders were aged about 20.
Anyone with any further information about the incident is asked to contact the Volume Crime Team at Salford on 0161 856 5250 or Crimestoppers anonymously on 0800 555 111.
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