Mark Webber emerged in front at the end of opening practice for the Singapore Grand Prix, as a last-minute rush for slick tyres on a drying track created an unusual order in the first session of the weekend.
The championship leader denied Michael Schumacher the chance to top a session for the first time in his comeback season, as Red Bull driver Webber sneaked in a 1m54.589s, 0.119 seconds ahead of the time Schumacher (Mercedes) had just set to briefly lead the way.
Adrian Sutil was third for Force India, ahead of Sebastian Vettel in the second Red Bull, Toro Rosso's Jaime Alguersuari and McLaren's Jenson Button - all of whom had been in first place for a few moments during the crazy closing stages.
One important piece of information that the drivers learned was that the Marina Bay track takes a long time to dry without sunlight hitting it.
Even though no rain had fallen for over an hour before the start of practice, it was only in the final 15 minutes that the track was really suitable for slick tyres - and even then puddles were still visible off-line in many places.
Kamui Kobayashi ended up only 12th for Sauber, but had been one of the pacesetters in the wetter period - as had Virgin's Timo Glock, who sat at the top of the times for 13 minutes in the middle of the session.
Nick Heidfeld was 13th on his return to the Sauber cockpit, though the late changes were so rapid that he had been in the top six with a minute to go.
Lewis Hamilton, testing McLaren's new front wing, had a similar experience - tumbling to 18th purely because he finished his final flying lap sooner than most.
Jerome d'Ambrosio was within 0.2s of team-mate Glock on his first run for Virgin, while Christian Klien settled back in with Hispania in 23rd place, 3.7s down on team-mate Bruno Senna.
Apart from a few trips over chicanes and visits to run-off areas, the session was incident-free - although Nico Hulkenberg (Williams) is set to collect a gearbox change penalty as a new unit will be necessary following a differential problem at Monza.
Pos Driver Team Time Laps 1. Webber Red Bull-Renault 1:54.589 10 2. Schumacher Mercedes 1:54.708 + 0.119 24 3. Sutil Force India-Mercedes 1:54.827 + 0.238 15 4. Vettel Red Bull-Renault 1:55.137 + 0.548 12 5. Alguersuari Toro Rosso-Ferrari 1:55.160 + 0.571 20 6. Button McLaren-Mercedes 1:55.333 + 0.744 12 7. Liuzzi Force India-Mercedes 1:55.510 + 0.921 15 8. Buemi Toro Rosso-Ferrari 1:55.523 + 0.934 15 9. Kubica Renault 1:55.672 + 1.083 11 10. Petrov Renault 1:55.914 + 1.325 20 11. Alonso Ferrari 1:56.090 + 1.501 12 12. Kobayashi Sauber-Ferrari 1:56.339 + 1.750 22 13. Heidfeld Sauber-Ferrari 1:56.458 + 1.869 18 14. Rosberg Mercedes 1:56.598 + 2.009 8 15. Kovalainen Lotus-Cosworth 1:56.603 + 2.014 12 16. Barrichello Williams-Cosworth 1:56.615 + 2.026 17 17. Hulkenberg Williams-Cosworth 1:56.840 + 2.251 14 18. Hamilton McLaren-Mercedes 1:56.884 + 2.295 9 19. Massa Ferrari 1:57.760 + 3.171 22 20. Glock Virgin-Cosworth 1:59.034 + 4.445 19 21. D'Ambrosio Virgin-Cosworth 1:59.275 + 4.686 16 22. Senna HRT-Cosworth 1:59.783 + 5.194 23 23. Klien HRT-Cosworth 2:03.424 + 8.835 17 24. Fauzi Lotus-Cosworth 2:05.694 + 11.105 11 All Timing Unofficial