Sebastian Vettel and Mark Webber sent a warning to Red Bull's rivals by giving their team a commanding one-two in second practice for the Singapore Grand Prix.
Once up to speed, Vettel dominated much of the session, putting in a 1m48.559s to go fastest ahead of early pace-setter Fernando Alonso after 25 minutes.
McLaren's Jenson Button deposed Vettel with a run on the softer tyres just after the halfway point - but when the German changed to super softs not only did he go quickest, but went on to repeatedly extend his advantage with a blistering run that took him a second clear of the field.
That margin initially remained even when Webber brought the second Red Bull up to second, though the Australian later closed to within 0.627s.
Alonso was the only man who looked capable of threatening Vettel. The Ferrari driver beat the Red Bull's first sector time and was quick in sector two as well, but then had a lurid moment on the Turn 17 kerb before sliding down the escape road at the next corner. Alonso reversed back out, only to stall when he reached the racetrack and have to abandon his Ferrari, ending his session 20 minutes early.
The other driver to make a significant mistake was Adrian Sutil, who took a violent ride over the Turn 10 chicane kerbs. The Force India took to the air and landed heavily on the next kerb, smashing its left front suspension.
Despite his excursion, Alonso's time still kept him fourth, between the two McLaren drivers, with Button remaining third and Lewis Hamilton taking fifth, as the five title contenders led the way.
Rubens Barrichello was best of the rest, taking an encouraging sixth for Williams ahead of Felipe Massa in the second Ferrari.
Mercedes was eighth and 10th with Nico Rosberg and Michael Schumacher, split by Robert Kubica - who spent a lot of the session in the Renault garage while his car received attention.
Nick Heidfeld was again right behind his Sauber team-mate Kamui Kobayashi as the duo took 12th and 13th. Fellow returnee Christian Klien was slowest of all - with Hispania a second adrift of its nearest rivals and 8s off the overall pace.
Pos Driver Team Time Laps 1. Vettel Red Bull-Renault 1:46.660 29 2. Webber Red Bull-Renault 1:47.287 + 0.627 27 3. Button McLaren-Mercedes 1:47.690 + 1.030 28 4. Alonso Ferrari 1:47.718 + 1.058 20 5. Hamilton McLaren-Mercedes 1:47.818 + 1.158 28 6. Barrichello Williams-Cosworth 1:48.302 + 1.642 31 7. Massa Ferrari 1:48.341 + 1.681 28 8. Rosberg Mercedes 1:48.679 + 2.019 26 9. Kubica Renault 1:48.855 + 2.195 15 10. Schumacher Mercedes 1:48.889 + 2.229 31 11. Hulkenberg Williams-Cosworth 1:49.153 + 2.493 32 12. Kobayashi Sauber-Ferrari 1:49.438 + 2.778 30 13. Heidfeld Sauber-Ferrari 1:49.558 + 2.898 26 14. Petrov Renault 1:49.608 + 2.948 30 15. Liuzzi Force India-Mercedes 1:49.896 + 3.236 28 16. Sutil Force India-Mercedes 1:49.984 + 3.324 11 17. Alguersuari Toro Rosso-Ferrari 1:50.191 + 3.531 31 18. Buemi Toro Rosso-Ferrari 1:50.896 + 4.236 35 19. Kovalainen Lotus-Cosworth 1:51.878 + 5.218 30 20. Glock Virgin-Cosworth 1:52.150 + 5.490 22 21. di Grassi Virgin-Cosworth 1:53.431 + 6.771 25 22. Trulli Lotus-Cosworth 1:53.526 + 6.866 27 23. Senna HRT-Cosworth 1:54.725 + 8.065 27 24. Klien HRT-Cosworth 1:55.542 + 8.882 25 All Timing Unofficial