Nico Rosberg led the way from Lewis Hamilton in the opening morning practice for the British Grand Prix after coming back from an early gearbox leak.
The German had to pit in the early goings due to a hydraulics leak in his gearbox, but after outstanding work from his engineers he was back on track for the final minutes, and only to go quickest by a mere 0.070s ahead of his team-mate.
Third on the charts was an impressive Max Verstappen for Toro Rosso, ahead of Kimi Raikkonen, Carlos Sainz and the birthday boy: Sebastian Vettel (28). All with similar times in the mid-1m 35s.
Then followed both Red Bulls, and Force India, with their latest nose upgrade, while Felipe Massa closed the top ten.
Williams also gave the wheel to Susie Wolff in FP1, substituting for Valtteri Bottas, as did Jolyon Palmer for Romain Grosjean, and Raffaele Marciello for Marcus Ericsson. They finished 13th-15th in that order.
For McLaren it was a new problem-filled session, with little laps in and a 'deployment problem' for Fernando Alonso.
PRACTICE ONE RESULTS:
1. Nico Rosberg, Mercedes — 1:34.274
2. Lewis Hamilton, Mercedes — 1:34.344
3. Max Verstappen, Toro Rosso — 1:35.530
4. Kimi Raikkonen, Ferrari — 1:35.588
5. Carlos Sainz, Toro Rosso — 1:35.669
6. Sebastian Vettel, Ferrari — 1:35.739
7. Daniel Ricciardo, Red Bull — 1:35.818
8. Daniil Kvyat, Red Bull — 1:35.876
9. Nico Hulkenberg, Force India — 1:36.157
10. Felipe Massa, Williams — 1:36.469