TWO teens crashed and burned to death in a sports car along Sixth Avenue in the early hours of Aug 25 last year - and no one saw how it happened.

The weather was fine, the road surface was dry and visibility was good. Yet the Mazda RX-5 went out of control and slammed into a tree and a brick wall.

The car burst into flames.

Unable to determine what exactly happened, State Coroner Victor Yeo on Thursday said that he had to arrive at an open verdict on the deaths of the two teenagers.

The coroner said that an inspection did not reveal any defect that could have caused the Mazda to go out of control.

Taxi driver Wan Abu Bakar Ahmad, 57, told police that he had stopped to allow a passenger to alight near Jalan Haji Alias slightly before 4am, when the Mazda overtook him at '100-plus kmh'.

The sports car then filtered left on the single-lane two-way road, which has a speed limit of 50kmh, to give way to an oncoming motorcyclist before it disappeared from his sight as it went down a slope.

Minutes later, the cabby found the car wedged between a tree and the perimeter wall of a house and ablaze.

Mr Widjaja died of severe burns while Mr Davies died of multiple injuries and severe burns. The convertible was also totally burnt.

Mr Davis, a Briton, was about to start at the University of British Columbia in Canada while Mr Widjaja, an Indonesian national and Singapore permanent resident, was doing his second year at the University of London.

The latter was here visiting former classmates from the United World College.

Station Inspector Raimi told the coroner court that Mr Widjaja and Mr Davies had been with friends at Cafe del Mal on Sentosa from 12.30am till 3.45am.

The group then decided to reconvene at the 24-hour Macdonald's outlet off Clementi Road.

Although the car belonged to his friend's father, Mr Widjaja took the wheel.

A post-mortem revealed a blood alcohol content of 32mg in Mr Widjaja - more than half lower than the legally prescribed 80mg for drink driving, the coroner noted.