Lewis Hamilton has recorded the quickest time in the second practice session ahead of this weekend's Chinese Grand Prix.
The British driver told his team that "something does not feel right" with his Mercedes, but it didn't stop him ending the session ahead of Ferrari's Fernando Alonso.
Teammate Nico Rosberg finished in third, with the Red Bull duo of Daniel Ricciardo and Sebastian Vettel setting the fourth- and fifth-fastest times respectively.
Williams driver Felipe Massa was sixth-quickest, while McLaren's Jenson Button concluded the day over a second slower than Hamilton in eighth position.
Full standings
1. Lewis Hamilton (Mercedes)
2. Fernando Alonso (Ferrari)
3. Nico Rosberg (Mercedes)
4. Daniel Ricciardo (Red Bull)
5. Sebastian Vettel (Red Bull)
6. Felipe Massa (Williams)
7. Kimi Raikkonen (Ferrari)
8. Jenson Button (McLaren)
9. Romain Grosjean (Lotus)
10. Daniil Kvyat (Toro Rosso)
11. Nico Hulkenberg (Force India)
12. Kevin Magnussen (McLaren)
13. Jean-Eric Vergne (Toro Rosso)
14. Valtteri Bottas (Williams)
15. Sergio Perez (Force India)
16. Esteban Gutierrez (Sauber)
17. Adrian Sutil (Sauber)
18. Pastor Maldonado (Lotus)
19. Jules Bianchi (Marussia)
20. Max Chilton (Marussia)
21. Kamui Kobayashi (Caterham)
22. Marcus Ericsson (Caterham)