Nico Rosberg recorded the fastest time in first practice for this weekend's Belgian Grand Prix as Formula 1 makes its return after the summer break.
The Mercedes driver topped the timesheets with a lap of 1:51.082 at Spa, a quarter of a second quicker than teammate and world championship leader Lewis Hamilton.
Red Bull's Daniel Ricciardo was third, while the Ferraris of Kimi Raikkonen, who signed a new one-year deal this week, and Sebastian Vettel completed the top five, with the Italian team participating in its 900th Grand Prix.
The session was briefly red-flagged midway through when Lotus's Pastor Maldonado, 11th fastest, lost control and smashed into a barrier.
The McLarens of Fernando Alonso and Jenson Button continue to struggle, with the pair 16th and 18th fastest.
1. Nico Rosberg (Mercedes)
2. Lewis Hamilton (Mercedes)
3. Daniel Ricciardo (Red Bull)
4. Kimi Raikkonen (Ferrari)
5. Sebastian Vettel (Ferrari)
6. Daniil Kvyat (Red Bull)
7. Max Verstappen (Toro Rosso)
8. Carlos Sainz (Toro Rosso)
9. Sergio Perez (Force India)
10. Valtteri Bottas (Williams)
11. Pastor Maldonado (Lotus)
12. Nico Hulkenberg (Force India)
13. Felipe Nasr (Sauber)
14. Felipe Massa (Williams)
15. Marcus Ericsson (Sauber)
16. Fernando Alonso (McLaren)
17. Jolyon Palmer (Lotus)
18. Jenson Button (McLaren)
19. Will Stevens (Marussia)
20. Roberto Mehri (Marussia)