Silverstone, Northamptonshire - Nico Rosberg knocked team-mate Lewis Hamilton off the top of the timesheets in the dying seconds as Mercedes dominated first practice for the British Grand Prix on Friday.
Rosberg, 10 points behind double world champion Hamilton after eight of the season's 19 races, lapped with a best time of 1m34.274s on a hot, sunny morning at Silverstone.
Hamilton was a mere 0.070s slower with Toro Rosso's Dutch teenager Max Verstappen an impressive third but 1.256s off the pace.
Rosberg, winner of three of the past four races, had sat out much of the session as mechanics changed his car's gearbox due to a hydraulic fault that stopped him on track after only five laps.
He had time for just 12 laps once the car had been fixed, compared to Hamilton's 26, but he made up for lost time by getting quickly up to speed.
EARLY SPIN
Hamilton, who can expect to have most of the support from an expected 140 000-strong crowd on Sunday, had an early spin at Stowe without consequence.
Ferrari's Kimi Raikkonen, who crashed heavily in the previous race in Austria, was fourth fastest with Spaniard Carlos Sainz fifth for Toro Rosso and Sebastian Vettel sixth in the second Ferrari.
Germany's Nico Hulkenberg, with the updated Force India getting its first proper run, was ninth fastest behind the Red Bulls of Daniel Riciardo and Daniil Kvyat.
Honda-powered McLaren's miserable run of form continued with Fernando Alonso and Jenson Button 17th and 18th respectively, after spending most of the session in the garage, with only the Manor Marussia drivers slower than them.
Development driver Susie Wolff made her sole appearance of the weekend for Williams and was 13th fastest. - Reuters
RESULTS – First Session
1 Nico Rosberg (Germany) Mercedes - 1m34.274s
2 Lewis Hamilton (Britain) Mercedes - 1:34.344
3 Max Verstappen (Netherlands) Toro Rosso - 1:35.530
4 Kimi Raikkonen (Finland) Ferrari - 1:35.588
5 Carlos Sainz Jr (Spain) Toro Rosso - 1:35.669
6 Sebastian Vettel (Germany) Ferrari 1:35.739
7 Daniel Ricciardo (Australia) Red Bull - 1:35.818
8 Daniil Kvyat (Russia) Red Bull - 1:35.876
9 Nico Hulkenberg (Germany) Force India - 1:36.157
10 Felipe Massa (Brazil) Williams - 1:36.469
11 Felipe Nasr (Brazil) Sauber - 1:36.855
12 Sergio Perez (Mexico) Force India - 1:36.889
13 Susie Wolff (Britain) Williams - 1:37.242
14 Jolyon Palmer (Britain) Lotus - 1:37.262
15 Raffaele Marciello (Italy) Sauber - 1:37.372
16 Pastor Maldonado (Venezuela) Lotus - 1:38.080
17 Fernando Alonso (Spain) McLaren - 1:38.222
18 Jenson Button (Britain) McLaren - 1:38.860
19 Will Stevens (Britain) Marussia - 1:38.981
20 Roberto Merhi (Spain) Marussia - 1:40.477