Mercedes driver Nico Rosberg has clocked the fastest time in the first practice session in Spa ahead of Sunday's Belgian Grand Prix.
The 31-year-old, who is 19 points behind leader Lewis Hamilton in the drivers' rankings, recorded a time of 1:48.348
Hamilton was 0.730 seconds slower than his Mercedes teammate, but he has a disadvantage heading into this weekend's race as he will serve a 15-place grid penalty.
Ferrari's Kimi Raikkonen finished third fastest, while his partner Sebastian Vettel was fifth in the standings behind Force India's Sergio Perez.
Fernando Alonso suffered some trouble as he failed to record a lap due to issues with his McLaren's power unit.
Meanwhile, Esteban Ocon clocked the 16th-quickest time as he prepares to make his race debut for Manor this weekend.
First practice standings:
1. Nico Rosberg (Mercedes)
2. Lewis Hamilton (Mercedes)
3. Kimi Raikkonen (Ferrari)
4. Sergio Perez (Force India)
5. Sebastian Vettel (Ferrari)
6. Daniel Ricciardo (Red Bull)
7. Max Verstappen (Red Bull)
8. Nico Hulkenburg (Force India)
9. Valtteri Bottas (Williams)
10. Esteban Gutierrez (Haas)
11. Romain Grosjean (Haas)
12. Felipe Massa (Williams)
13. Marcus Ericsson (Sauber)
14. Carlos Sainz Jr (Toro Rosso)
15. Felipe Nasr (Sauber)
16. Esteban Ocon (Manor)
17. Daniil Kvyatt (Toro Rosso)
18. Jenson Button (McLaren)
19. Pascal Wehrlein (Manor)
20. Kevin Magnussen (Renault)
21. Jolyon Palmer (Renault)
22. Fernando Alonso (McLaren)
