Lewis Hamilton hit back at Mercedes teammate Nico Rosberg by recording the fastest time of second practice for this weekend's Russian Grand Prix.
Rosberg, winner of the season's first three races, went fastest in this morning's first session but could only manage third this afternoon, with Ferrari's Sebastian Vettel sandwiched between the two Mercedes.
Hamilton's time of 1:37.583 was over half a second quicker than Vettel, whose car stopped on the track with an electrical failure halfway through the session.
Rosberg, who leads Hamilton by 36 points in the drivers' championship, was 0.867s adrift of the Englishman, but did not set a representative lap on the faster tyre.
Vettel's Ferrari teammate Kimi Raikkonen was fourth, with Daniel Ricciardo of Red Bull completing the top five.
McLaren had an encouraging session as both Jenson Button (eighth) and Fernando Alonso (10th) recorded top-10 times.
1. Lewis Hamilton (Mercedes)
2. Sebastian Vettel (Ferrari)
3. Nico Rosberg (Mercedes)
4. Kimi Raikkonen (Ferrari)
5. Daniel Ricciardo (Red Bull)
6. Valtteri Bottas (Williams)
7. Daniil Kvyat (Red Bull)
8. Jenson Button (McLaren)
9. Felipe Massa (Williams)
10. Fernando Alonso (McLaren)
11. Carlos Sainz (Toro Rosso)
12. Max Verstappen (Toro Rosso)
13. Nico Hulkenberg (Force India)
14. Sergio Perez (Force India)
15. Kevin Magnussen (Renault)
16. Romain Grosjean (Haas)
17. Esteban Gutierrez (Haas)
18. Jolyon Palmer (Renault)
19. Felipe Nasr (Sauber)
20. Rio Haryanto (Manor)
21. Pascal Wehrlein (Manor)
22. Marcus Ericsson (Sauber)
Pascal Lemesre
