Red Bull's Sebastian Vettel lapped fastest under the floodlights in the 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.
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.
