The driver, Mr Kerk Teck Guan, and his passenger, Mr Ng Wei Liang, suffered multiple injuries and both died 1 1/2 hours later in hospital.
The accident happened between Lorongs 12 and 14 in Geylang, before the horrified eyes of their friends who were in two other cars behind them. The crash also drew a large crowd to the scene.
The group of friends had gone to Geylang for supper earlier that night.
The dead men were both 26 and had been friends for more than 14 years.
Mr Ng, a sales executive at Courts, owned a car of the same model which had been involved in an accident along the Pan-Island Expressway three weeks ago. The car is now in the workshop.
He was lucky not to have been hurt then, when the car spun, said his grieving widow Angeline Ang, 26, last night. The couple were married for five years and have a five-year-old daughter.