Lewis Hamilton was fastest in opening practice for the Brazilian GP ahead of Nico Rosberg and Sebastian Vettel.
The world champion has been making the wrong sort of headlines this week after a late-night traffic accident near his Monaco home, but showed no ill-effects on Friday when he lapped the 4.309km Interlagos track in a time of 1:13.543s.
Hamilton admitted on Thursday that he wasn't feeling 100 per cent but he was still the only driver to dip below the 1:13 barrier and his time put him 0.519s faster than Rosberg, who won last year's race and is seeking his second win in a row this weekend.
Sebastian Vettel was third fastest, ahead of Daniel Ricciardo, who was running Renault's upgraded engine in his Red Bull and finished up about 0.9s off the pace ahead of Kimi Raikkonen's Ferrari.
Ricciardo will take a grid penalty this weekend and has said that the upgrade is expected to give them a tenth or two in lap time - a prediction that seemed pretty much accurate when comparing the pace of sixth-placed team-mate Daniil Kvyat.
Red Bull, who are expected to officially confirm this weekend that they will continue in F1 next season, will now make a decision on whether to fit the new engine to the Russian's car as well.
Valtteri Bottas was seventh fastest, with Max Verstappen, Nico Hulkenberg and Pastor Maldonado completing the top 10 ahead of Carlos Sainz and Jolyon Palmer.
Jenson Button was 13th fastest, meanwhile, with McLaren team-mate Fernando Alonso 16th.
Brazilian GP Practice One Timesheet:
1. Lewis Hamilton, Mercedes, 1:13.543
2. Nico Rosberg, Mercedes, 1:14.062
3. Sebastian Vettel, Ferrari, 1:14.168
4. Daniel Ricciardo, Red Bull, 1:14.449
5. Kimi Raikkonen, Ferrari, 1:14.549
6. Daniil Kvyat, Red Bull, 1:14.696
7. Valtteri Bottas, Williams, 1:14.886
8. Max Verstappen, Toro Rosso, 1:14.960
9. Nico Hulkenberg, Force India, 1:15.174
10. Pastor Maldonado, Lotus, 1:15.192
11. Carlos Sainz, Toro Rosso, 1:15.314
12. Jolyon Palmer, Lotus, 1:15.352
13. Jenson Button, McLaren, 1:15.379
14. Felipe Nasr, Sauber, 1:15.381
15. Sergio Perez, Force India, 1:15.408
16. Fernando Alonso, McLaren, 1:15.413
17. Felipe Massa, Williams, 1:15.469
18. Marcus Ericsson, Sauber, 1:15.798
19. Alex Rossi, Manor, 1:17.860
20. Will Stevens, Manor, 1:18.090
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