Unhappy with a taxi driver after a close brush on the road, a motorist later attacked the cabby and punched his face repeatedly.
Instead of stopping the assault, a passenger from the car, Dickson Goh Teck Long, joined in and kicked cabby Choo Beng Heng's back a few times.
Goh, 25, a car-rental shop worker, was yesterday jailed for five weeks after he pleaded guilty to causing hurt to Mr Choo, 48.
Goh and two friends, interior designer Ho Chee Kwang, 30, and student Jason Ang Li Jie, 21, were inside a parked car along a one-way lane in Serangoon Gardens at about 12.15am on June 9 last year when Ho suddenly opened his car door.
The door almost hit Mr Choo's taxi as he was driving past.
A quarrel broke out between Mr Choo and Ho, and the cabby drove away when it ended.
Still unhappy, Ho followed the cabby in his car as he drove towards a petrol station in Yio Chu Kang Road.
Mr Choo, who spotted Ho's white Honda Civic following closely behind, stopped his taxi, alighted and walked towards the younger man.
Deputy Public Prosecutor Chong Kee En said: "Ho started to punch the victim's face repeatedly with both of his hands. Goh and Ang then joined in the assault separately."
The three men fled when the cabby tried to call for help.
Mr Choo was taken to Tan Tock Seng Hospital with injuries, including facial fractures and tenderness to his right chest wall. He was hospitalised for two days and given three weeks of outpatient medical leave.
DPP Chong urged District Judge Low Wee Ping to jail Goh for six weeks, stressing that Mr Choo's injuries were quite serious.
Pleading for leniency, Goh's lawyer, Mr Mervyn Tan, said his client was not the main perpetrator. "He realises he had acted foolishly and such actions were not premeditated but were done in a moment of indiscretion,"said Mr Tan.
Ho and Ang have not been dealt with in court.
Goh could have been jailed for up to two years and fined up to $5,000.