SINGAPORE - Renault's Fernando Alonso topped the times in Saturday evening's final free practice session for the Singapore Grand Prix, ahead of world championship leader Lewis Hamilton.

The Spaniard clocked a best lap of 1:44.506 to wind up 0.613 of a second ahead of Hamilton in a McLaren and 0.740 of a second in front of Ferrari's Felipe Massa, who is one point behind the Briton in the title race.

In hot and humid conditions but on a dry track, Renault's other driver Nelson Piquet was fourth and Nico Rosberg in his Williams came fifth under the spotlights on the bumpy Marina Bay circuit.

Defending champion Kimi Raikkonen, desperate for a good finish in Singapore to keep alive his slim hopes of retaining his title, was forced out of the session with 14 minutes left.

The Finn was approaching turn 7 when a huge puff of smoke blew from his Ferrari and he steered into a run-off lane before stalling.

Another casualty was Force India's Giancarlo Fisichella whose car lifted off the ground after he misjudged a chicane and he went careering into the barriers.

A broken gearbox limited Red Bull's David Coulthard to just seven minutes on the track.

New kid on the block Sebastian Vettel, winner in Italy earlier this month, held the top spot for some time before Piquet snatched the lead with 25 minutes of the hour-long session gone.

The Brazilian held on until Massa powered in front with five minutes left.

Hamilton looked to have the top spot sewn up when he clocked 1:45.199 with three minutes remaining before a late burst allowed two-time champion Alonso to pip him at the post as he had done in the second practice on Friday.

Qualifying is held later Saturday.

- AFP/ir