Force India's Nico Hulkenberg has clocked the fastest time in the first practice session ahead of Sunday's Russian Grand Prix in Sochi.
The start of the session was delayed by around half an hour due to a large diesel spillage on the track, and the drivers were tentative when they emerged as sections of the track were slippery.
Marcus Ericsson was the first driver to set a time inside 25 minutes of the practice as he clocked 1:55.402, while McLaren duo Jenson Button and Fernando Alonso also moved towards the top of the timesheet.
The Ferraris struggled on the slippery track as Sebastian Vettel and Kimi Raikkonen both ran wide at Turn 8, but the former was able to clock the third-fastest time of 1:44.986.
Hulkenberg's time of 1:44.355 was the best of the session, while Nico Rosberg was just behind in a time of 1:44.407, but his teammate and championship leader Lewis Hamilton finished seventh on the timesheet after spinning on the track.
Full standings:
1. Nico Hulkenberg (Force India)
2. Nico Rosberg (Mercedes)
3. Sebastian Vettel (Ferrari)
4. Sergio Perez (Force India)
5. Daniel Ricciardo (Red Bull)
6. Carlos Sainz Jr (Toro Rosso)
7. Lewis Hamilton (Mercedes)
8. Valetteri Bottas (Williams)
9. Max Verstapen (Toro Rosso)
10. Kimi Raikkonen (Ferrari)
11. Jenson Button (McLaren)
12. Felipe Massa (Williams)
13. Felipe Nasr (Sauber)
14. Fernando Alonso (McLaren)
15. Pastor Maldonado (Lotus)
16. Daniil Kvyat (Red Bull)
17. Jolyon Palmer (Lotus)
18. Roberto Merhi (Manor)
19. Marcus Ericsson (Sauber)
20. Will Stevens (Manor)