Vettel quickest in Singapore practice

Red Bull's Sebastian Vettel lapped fastest under the floodlights in Friday's Singapore Grand Prix free practice while Australian team mate Mark Webber crashed.

Fernando Alonso, the winner of last year's scandal-tainted night race, shrugged off the withdrawal of Renault's main sponsors a day earlier by clocking the second fastest time in a car hastily stripped of its ING and Mutua Madrilena markings.

The Spaniard, who had been fourth fastest in the early session, lapped 0.274 seconds behind Vettel's 1:48.650.

The top 15 drivers in the second session all lapped quicker than Brazilian title contender Rubens Barrichello, fastest in the first practice for Brawn GP in 1:50.179.

French rookie Romain Grosjean provided the main talking point earlier in the evening when he smashed his Renault at the same corner where Brazilian Nelson Piquet deliberately crashed a year ago.

McLaren's Heikki Kovalainen was third fastest in 1:48.952, ahead of BMW-Sauber's Nick Heidfeld and championship leader Jenson Button in the other Brawn.

Webber was the quickest driver on the track before his accident after 14 laps but his time of 1:49.317 was still the sixth best of the second session.

Barrichello trails Button by 14 points in the standings with four races left. Vettel has won two races this year and is third in the championship, 26 points behind the leader and 2.5 ahead of Webber.

The first session provided an astonishing flashback to Piquet's crash in the inaugural 2008 race, with Grosjean losing control on turn 17 and slamming into the opposite wall.

The Renault brushed the wall with its rear, spinning and hitting the barriers opposite.

Renault were handed a suspended permanent ban for race-fixing earlier this week after Piquet confessed to crashing on purpose last year in a plot to help Alonso win after the safety car was deployed.

Grosjean, who replaced Brazilian Piquet in August and was passed fit only on Friday morning after feeling unwell on Thursday, had completed nine laps when he crashed. He has not previously raced at the track.

Both Grosjean and Webber, who hit a wall on turn 23, were able to walk away from their crashes.