Sebastian Vettel put the ongoing exhaust rules row behind him to put Red Bull Racing on top in the first dry practice session of the British Grand Prix weekend at Silverstone.
After all of Friday's running was affected by rain, teams finally got a reasonable amount of dry mileage in third practice this morning - though showers and drizzle continued to affect the circuit.
One particular shower in the middle of the session looked like it might be prolonged enough to prevent any further improvements, but in the event it dried quickly - prompting a frantic final half-hour.
With two minutes to go, Vettel put in a 1m31.401s to knock Ferrari's Fernando Alonso off the top spot by just 0.063 seconds.
Vettel looked set to go faster still on his next lap, but it tailed off in the latter sectors as the rain increased yet again.
Mark Webber had been quickest early on, then lost a lot of the middle part of the session in the garage while repairs were carried out to his Red Bull. He rejoined to take third, ahead of the second Ferrari of Felipe Massa.
Pastor Maldonado was quickest for a spell late on in a very strong run for Williams. He ended up fifth.
McLaren had a quiet morning, with Jenson Button and Lewis Hamilton only sixth and 13th respectively.
Both Saubers were in the top 10, Kamui Kobayashi and Sergio Perez seventh and ninth, split by Mercedes' Nico Rosberg - another man who held the top spot for a while amid the constant changes of the second half of the hour.
The sister Mercedes of Michael Schumacher also needed attention to mechanical issues mid-session before returning to the track. He was only 11th, his last lap having been slowed by the the rain.
Paul di Resta completed the top 10 on home ground for Force India.
The only incident of the session was an out-lap spin for Tonio Liuzzi, who was slower than new Hispania team-mate Daniel Ricciardo as the duo brought up the rear.
Pos Driver Team/Car Time Gap Laps
1. Sebastian Vettel Red Bull-Renault 1m31.401s 17
2. Fernando Alonso Ferrari 1m31.464s + 0.063s 20
3. Mark Webber Red Bull-Renault 1m31.829s + 0.428s 12
4. Felipe Massa Ferrari 1m32.169s + 0.768s 20
5. Pastor Maldonado Williams-Cosworth 1m32.496s + 1.095s 20
6. Jenson Button McLaren-Mercedes 1m32.956s + 1.555s 18
7. Kamui Kobayashi Sauber-Ferrari 1m33.014s + 1.613s 20
8. Nico Rosberg Mercedes 1m33.044s + 1.643s 23
9. Sergio Perez Sauber-Ferrari 1m33.264s + 1.863s 21
10. Paul di Resta Force India-Mercedes 1m33.423s + 2.022s 22
11. Michael Schumacher Mercedes 1m33.551s + 2.150s 11
12. Adrian Sutil Force India-Mercedes 1m33.660s + 2.259s 22
13. Lewis Hamilton McLaren-Mercedes 1m33.842s + 2.441s 16
14. Rubens Barrichello Williams-Cosworth 1m33.905s + 2.504s 21
15. Vitaly Petrov Renault 1m34.042s + 2.641s 22
16. Jaime Alguersuari Toro Rosso-Ferrari 1m34.329s + 2.928s 20
17. Sebastien Buemi Toro Rosso-Ferrari 1m34.799s + 3.398s 20
18. Nick Heidfeld Renault 1m34.822s + 3.421s 21
19. Heikki Kovalainen Lotus-Renault 1m35.225s + 3.824s 21
20. Jarno Trulli Lotus-Renault 1m36.905s + 5.504s 21
21. Timo Glock Virgin-Cosworth 1m37.614s + 6.213s 18
22. Jerome D'Ambrosio Virgin-Cosworth 1m38.068s + 6.667s 20
23. Daniel Ricciardo HRT-Cosworth 1m38.289s + 6.888s 19
24. Tonio Liuzzi HRT-Cosworth 1m38.568s + 7.167s 17