Zhai Qiuyun, a delivery worker for the electronics retailer Suning, heard calls for help while driving his delivery vehicle in Maogang Town, Songjiang District, around 4pm on August 15.
Spectators who had gathered by the river told him that a car had gone into the water with the driver inside.
The white car was sinking quickly, Zhai recalled.
Without hesitation, he took a wrench used for removing tires and jumped into river.
Zhai swam to the car, the front of which was totally submerged. He gesticulated the driver to get into the back seat and tried to smash a window with the wrench. But that didn't work because he couldn't apply his strength in the water.
A flash of inspiration saved the day.
He climbed onto the roof of the car and being out of the water, managed to smash the rear window. He dragged out the driver.
Once released from the vehicle, the driver was unable to swim to safety, so Zhai brought him to the bank. By the time they got there, the car was had disappeared under the water.
"I could not think twice because it was the moment of life and death and a race against time," Zhai said. "It would be too late if the car was totally submerged."
"I was also nervous at that moment because the river is deep, but if it happens again, I will do the same thing," he said. Zhai slightly injured the fingers on his right hand, but returned to work after a short rest.
Songjiang District Government plans to apply for a "good samaritan" title for Zhai, and his company has already rewarded him with 5,000 yuan (0).
Police located him via his vehicle plate. Until then, his good deeds were known only to his colleagues and the spectators at the drama.