Jenson Button took advantage of drier conditions to set the pace in Friday's second practice ahead of the Turkish Grand Prix.
The McLaren racer was half a second quicker than team-mate Lewis Hamilton, who ended third, Nico Rosberg splitting the English pair.
Championship leader Sebastian Vettel sat out second practice after damaging his Red Bull in a crash during a wet morning on track but team-mate Mark Webber was fifth.
The McLaren and Ferrari drivers took the early initiative, swapping lap times through the opening exchanges.
However, with Fernando Alonso heading into the garage with a hydraulic problem and McLaren heading in after their early running, it was left to Mercedes to set the pace with both Rosberg and Michael Schumacher taking a turn in the P1 slot.
The McLarens, though, soon returned, taking the fight to the Mercs with the two outfits exclusively occupying the top four slots through the final 30 minutes of the session and, more importantly, when the chequered flag fell.
Schumacher claimed the fourth quickest time, Felipe Massa was back in sixth, while Alonso finished down in 11th place.
Second session times:
1. Jenson Button (GBR) McLaren 1:26.456, 2. Nico Rosberg (GER) Mercedes GP 1:26.521, 3. Lewis Hamilton (GBR) McLaren 1:27.033, 4. Michael Schumacher (GER) Mercedes GP 1:27.063, 5. Mark Webber (AUS) Red Bull 1:27.149, 6. Felipe Massa (BRA) Ferrari 1:27.340, 7. Vitaly Petrov (RUS) Lotus-Renault 1:27.517, 8. Paul di Resta (SCO) Force India 1:27.725, 9. Sergio Perez (MEX) Sauber 1:27.844, 10. Adrian Sutil (GER) Force India 1:28.052, 11. Fernando Alonso (ESP) Ferrari 1:28.069, 12. Sebastien Buemi (SWI) Toro Rosso 1:28.153, 13. Nick Heidfeld (GER) Lotus-Renault 1:28.475, 14. Jaime Alguersuari (ESP) Toro Rosso 1:28.765, 15. Pastor Maldonado (VEN) Williams F1 1:28.828, 16. Rubens Barrichello (BRA) Williams F1 1:28.946, 17. Jarno Trulli (ITA) Lotus 1:29.409, 18. Kamui Kobayashi (JPN) Sauber 1:29.637, 19. Heikki Kovalainen (FIN) Lotus 1:30.281, 20. Jaine d'Ambrosio (BEL) Virgin Racing 1:31.035, 21. Timo Glock (GER) Virgin Racing 1:31.221, 22. Narain Karthikeyan (IND) Hispania 1:31.320, 23. Vitantonio Liuzzi (ITA) Hispania 1:31.989, 24. Sebastian Vettel (GER) Red Bull.