Nico Rosberg has set the pace in the first practice session ahead of this weekend's Russian Grand Prix.
The 29-year-old came in ahead of Mercedes teammate Lewis Hamilton, with Jenson Button of McLaren and Ferrari's Fernando Alonso finishing in third and fourth respectively.
McLaren's Kevin Magnussen ended the session fifth fastest, while Max Chilton, who was Marussia's only driver in Sochi as a mark of respect to Jules Bianchi, finished in 21st.
Daniil Kvyat, the only Russian on the grid for the inaugural F1 race weekend in his homeland, came seventh, one place ahead of Force India's Sergio Perez in sixth.
The second practice session in scheduled to get underway at 11am.
Full Standings:
1. Nico Rosberg (Mercedes)
2. Lewis Hamilton (Mercedes)
3. Jenson Button (McLaren)
4. Fernando Alonso (Ferrari)
5. Kevin Magnussen (McLaren)
6. Sergio Perez (Force India)
7. Daniil Kvyat (Toro Rosso)
8. Kimi Raikkonen (Ferrari)
9. Jean-Eric Vergne (Toro Rosso)
10. Valtteri Bottas (Williams)
11. Felipe Massa (Williams)
12. Daniel Ricciardo (Red Bull)
13. Nico Hulkenberg (Force India)
14. Sebastian Vettel (Red Bull)
15. Adrian Sutil (Sauber)
16. Pastor Maldonado (Lotus Renault)
17. Sergey Sirotkin (Sauber)
18. Romain Grosjean (Lotus Renault)
19. Roberto Merhi (Caterham)
20. Marcus Ericsson (Caterham)
21. Max Chilton (Marussia)