Nico Rosberg put Mercedes on top in a mostly dry second practice session for the British Grand Prix at Silverstone.
After the morning downpour and consequent dearth of running, teams wasted no time in getting straight out on a still-damp track at the start of the afternoon.
The circuit was dry enough for slicks within 10 minutes and Rosberg was among the pacesetters from the outset.
Force India's Adrian Sutil, morning practice leader Daniel Ricciardo of Toro Rosso and world champion Sebastian Vettel all had multiple spells on top as the times settled down over the following half an hour.
But then with 40 minutes remaining, Rosberg put in a 1m32.248s to claim a first place he would not lose, as teams then made their habitual switch to longer runs.
Vettel was second at that point, but his Red Bull team-mate Mark Webber demoted him to third when he rejoined after a long spell in the garage.
Force India took fourth and eighth on the first day of running at its home track, with Paul di Resta quicker than Sutil by the end.
Di Resta's fellow Briton Lewis Hamilton was just one place further back in fifth, but Jenson Button's McLaren was only 11th.
Ricciardo and Toro Rosso team-mate Jean-Eric Vergne showed very encouraging pace in sixth and seventh.
Lotus duo Romain Grosjean and Kimi Raikkonen were down in ninth and 13th.
Ferrari had a disappointing session too. Fernando Alonso was only 10th, while his team-mate Felipe Massa crashed at Stowe after just seven laps.
The Brazilian ran slightly wide through the corner when the track was still a little damp and spun back into the opposite wall, mangling the Ferrari's front end.
Pos Driver Team Time Gap Laps
1. Nico Rosberg Mercedes 1m32.248s 33
2. Mark Webber Red Bull-Renault 1m32.547s + 0.299s 26
3. Sebastian Vettel Red Bull-Renault 1m32.680s + 0.432s 31
4. Paul di Resta Force India-Mercedes 1m32.832s + 0.584s 34
5. Lewis Hamilton Mercedes 1m32.911s + 0.663s 28
6. Daniel Ricciardo Toro Rosso-Ferrari 1m33.171s + 0.923s 34
7. Jean-Eric Vergne Toro Rosso-Ferrari 1m33.290s + 1.042s 38
8. Adrian Sutil Force India-Mercedes 1m33.313s + 1.065s 34
9. Romain Grosjean Lotus-Renault 1m33.322s + 1.074s 38
10. Fernando Alonso Ferrari 1m33.494s + 1.246s 32
11. Jenson Button McLaren-Mercedes 1m33.740s + 1.492s 29
12. Nico Hulkenberg Sauber-Ferrari 1m33.896s + 1.648s 36
13. Kimi Raikkonen Lotus-Renault 1m34.120s + 1.872s 30
14. Sergio Perez McLaren-Mercedes 1m34.130s + 1.882s 29
15. Esteban Gutierrez Sauber-Ferrari 1m34.998s + 2.750s 32
16. Valtteri Bottas Williams-Renault 1m35.070s + 2.822s 29
17. Pastor Maldonado Williams-Renault 1m35.127s + 2.879s 35
18. Jules Bianchi Marussia-Cosworth 1m35.802s + 3.554s 27
19. Giedo van der Garde Caterham-Renault 1m35.984s + 3.736s 32
20. Charles Pic Caterham-Renault 1m36.079s + 3.831s 35
21. Max Chilton Marussia-Cosworth 1m37.329s + 5.081s 33
22. Felipe Massa Ferrari 1m43.466s + 11.218s 7