SINGAPORE - Formula One world champion Sebastian Vettel made it a clean sweep of practice domination for the Singapore Grand Prix, clocking the fastest time for the third straight session hours ahead of qualifying on Saturday.
The 60-minute session was red flagged with three minutes remaining after Vitaly Petrov crashed into the wall on turn 21 and parked his stricken Caterham at the entrance to the pitlane, but Vettel had looked comfortably quicker than his title rivals before the Russian's mishap.
Vettel suffered a disappointing outing in Monza last time, failing to finish with an alternator problem, but the German looks back to his best around the Marina Bay Street Circuit and appears on course to repeat his victory from 12 months ago.
The German, who is 39 points behind championship leader Fernando Alonso with seven rounds remaining, lapped in 1 minute 47.947 seconds, edging McLaren's Lewis Hamilton by 0.325 seconds with Alonso 0.351 seconds further back in third.
Nico Hulkenberg continued to show good pace in his Force India and crossed the line fourth fastest, but his position was elevated by the fact that Red Bull's Mark Webber and the McLaren of Jenson Button were unable to complete timed laps on the super-soft tires due to the red flag.
Tyre provider Pirelli have said the super-softs are 1.5 seconds quicker per lap than the soft tyres with motorsport director Paul Hembery suggesting the teams would adopt a two or three-stop strategy for Sunday's race.