Arsenal players Mesut Ozil and Sead Kolasinac were targeted, the club confirmed, but both escaped uninjured.
Footage on social media appears to show Kolasinac chasing the robbers in Platts Lane, near Golders Green, at about 17:00 BST.
Arsenal said in a statement: "We have been in contact with both players and they are fine."
In a video that has circulated on social media, full-back Kolasinac is seen fighting off two men who are wielding knives.
The player can be seen jumping out of a vehicle to confront the masked men who had pulled alongside the car on mopeds.
In the footage, both car jackers were seen to be armed and were filmed brandishing knives at 26-year-old Kolasinac.
A spokesman for the Metropolitan Police said: "It was reported that suspects on motorbikes had attempted to rob a man who was driving a car.
"The driver, along with his passenger, managed to get away unharmed and travelled to a restaurant in Golders Green, where they were spoken to by officers."
There have been no arrests so far.
Kolasinac and midfielder Ozil are not the first footballers to be targeted on London's roads.
In 2016, then West Ham striker Andy Carroll was threatened at gunpoint on his way home from training.
