Sebastian Vettel and Mark Webber held off the Mercedes and Lotus challenge to give Red Bull a one-two in opening practice for the Indian Grand Prix.
Mercedes driver Nico Rosberg ensured that Vettel did not have things all his own way during the mid-session short runs when most of the quick laps were set.
Rosberg did a 1m27.937s then a 1m27.217s in quick succession to remove the McLarens from their early position on top.
Vettel then beat his compatriot by 0.021 seconds, but within a minute Rosberg went quicker again and produced a 1m26.899s on the 10th lap of his run.
After a slower lap, Vettel got back up to speed again with a 1m26.683s that would keep him ahead for the rest of the morning.
Webber then snuck his Red Bull between the two Germans in the closing minutes.
Romain Grosjean was fourth for Lotus, while team-mate Kimi Raikkonen never attempted a lower-fuel run and was 1.7s slower in 17th.
Lewis Hamilton had also languished in the midfield for much of the session, before jumping to sixth late on, just ahead of Jenson Button and Sergio Perez's McLarens.
It was a tough start for Ferrari, with Felipe Massa eighth and Fernando Alonso sidelined by a gearbox problem after six laps.
Williams got itself into the top 10 with Valtteri Bottas just behind Nico Hulkenberg's Sauber in 10th. Bottas's team-mate Pastor Maldonado also had a spell in the top half of the field, though he also had a spin.
James Calado was the session's other spinner, as he stood in for the unwell Paul di Resta at Force India.
Pos Driver Team Time Gap Laps 1. Sebastian Vettel Red Bull-Renault 1m26.683s 24 2. Mark Webber Red Bull-Renault 1m26.871s +0.188s 17 3. Nico Rosberg Mercedes 1m26.899s +0.216s 23 4. Romain Grosjean Lotus-Renault 1m26.990s +0.307s 20 5. Lewis Hamilton Mercedes 1m27.227s +0.544s 21 6. Jenson Button McLaren-Mercedes 1m27.335s +0.652s 23 7. Sergio Perez McLaren-Mercedes 1m27.416s +0.733s 23 8. Felipe Massa Ferrari 1m27.692s +1.009s 21 9. Nico Hulkenberg Sauber-Ferrari 1m27.770s +1.087s 19 10. Valtteri Bottas Williams-Renault 1m27.800s +1.117s 23 11. Jean-Eric Vergne Toro Rosso-Ferrari 1m28.035s +1.352s 25 12. Fernando Alonso Ferrari 1m28.214s +1.531s 6 13. Daniel Ricciardo Toro Rosso-Ferrari 1m28.336s +1.653s 18 14. Pastor Maldonado Williams-Renault 1m28.342s +1.659s 21 15. Adrian Sutil Force India-Mercedes 1m28.468s +1.785s 20 16. Esteaban Gutierrez Sauber-Ferrari 1m28.538s +1.855s 18 17. Kimi Raikkonen Lotus-Renault 1m28.730s +2.047s 18 18. James Calado Force India-Mercedes 1m29.197s +2.514s 22 19. Giedgo van der Garde Caterham-Renault 1m29.413s +2.730s 24 20. Jules Bianchi Marussia-Cosworth 1m29.560s +2.877s 20 21. Charles Pic Caterham-Renault 1m30.026s +3.343s 23 22. Max Chilton Marussia-Cosworth 1m30.471s +3.788s 17