Lewis Hamilton finished Friday on top in Brazil, but Nico Rosberg closed the gap during Practice Two.
Just three hundredths of a second separated the two Mercedes cars around the Interlagos circuit. The British driver had been 0.23 ahead of Rosberg in the morning session.
And it looks like being a straight fight between the two title rivals, with third quickest Valtteri Bottas almost half a second further down the road.
That pace was made all the more impressive given Mercedes were managing the mileage and reliability of their power units.
Worryingly for Ferrari they were again off the pace and only the fourth quickest team, behind both Mercedes cars, both Williamses and both Red Bulls.
Kimi Raikkonen lost running in the session due to a brake problem when a visor tear-off became lodged in a cooling duct.
Raikkonen had earlier been involved in an incident on track with Carlos Sainz, when the Ferrari passed the Toro Rosso around the outside of the penultimate turn, before chopping across the front of the Spaniard to enter the pits.
The incident was placed under investigation but, after speaking to both drivers after the session, the stewards ruled that 'neither driver drove unnecessarily slowly, erratically or potentially dangerously'.
The two McLaren drivers were on the cusp of the top 10, but both cars struck strife as the long-runs commenced.
Fernando Alonso was forced to park his car on the outside of Turn Three due to a water pressure failure on the ERS system. But after a bit of football with a pebble, he did find himself a new job operating the remote camera on the oustide of the corner.
The sister car of Jenson Button also had problems, with the Briton stranded in the garage as the team investigated a gearbox sensor problem. His session then came to a early end after an exhaust problem.
Brazilian GP Practice Two
1. Lewis Hamilton, Mercedes, 1:12.271
2. Nico Rosberg, Mercedes, 1:12.301
3. Valtteri Bottas, Williams, 1:12.761
4. Felipe Massa, Williams, 1:12.789
5. Daniel Ricciardo, Red Bull, 1:12.828
6. Max Verstappen, Red Bull, 1:12.928
7. Sebastian Vettel, Ferrari, 1:13.002
8. Kimi Raikkonen, Ferrari, 1:13.002
9. Nico Hulkenberg, Force India, 1:13.299
10. Jenson Button, McLaren, 1:13.440
11. Fernando Alonso, McLaren, 1:13.572
12. Daniil Kvyat, Toro Rosso, 1:13.689
13. Carlos Sainz, Toro Rosso, 1:13.801
14. Sergio Perez, Force India, 1:13.918
15. Romain Grosjean, Haas, 1:14.074
16. Kevin Magnussen, Renault, 1:14.109
17. Felipe Nasr, Sauber, 1:14.309
18. Esteban Ocon, Manor, 1:14.317
19. Jolyon Palmer, Renault, 1:14.436
20. Esteban Gutierrez, Haas, 1:14.558
21. Marcus Ericsson, Sauber, 1:14.695
22. Pascal Wehrlein, Manor, 1:14.958
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