In video captured on a dash cam, a man on a bike is seen riding up a busy high street when a parked car pulls out quickly, nearly colliding with him.
The man jumps off his bike to avoid a collision, dropping it in the middle of the street, and runs after the blue Volkswagen which quickly comes to a halt.
Visibly angered, the cyclist pulls out a large knife and kicks the car.
He then hits the vehicle with the blade repeatedly in an attempt to smash the driver’s window, as bystanders look on.
The young man, who is dressed in a black coat and trousers, tries to pull open the car’s back door before going around the back of the car to continue the assault on the other side.
Meanwhile, a bus pulls to a stop further up the road, and two more young men come running down the middle of the street towards the car.
There is no indication that they are associated with either the cyclist or the driver.
Eventually, the driver got out of the car – which had its windscreen wipers on throughout the attack – and sprinted down the street.
A Metropolitan Police spokeswoman said: "Police were called on Wednesday, 30 May at around 17:00 hours to reports of males smashing a car window in London Road, Croydon.
"Officers attended and established that the driver of the car was approached by a male in possession of a knife who smashed his window.
"The victim, a 19-year-old man, in an attempt to escape collided with another vehicle, exiting on foot. He was followed by the suspect.
"The victim later returned to his car after the suspect made off. No reported injuries. Enquiries continue."
The incident comes at a time when knife crime is rising in the capital.