Sebastian Vettel and Mark Webber led the way for Red Bull once more in final practice for the United States Grand Prix, as Sauber's Nico Hulkenberg produced a star cameo performance.
Friday pacesetter Vettel took little time to hit the front again on Saturday morning with an early 1m37.433s lap.
That kept him in front until everyone switched to medium tyres and qualifying simulations for the final few minutes.
Hulkenberg found the most impressive gain on the softer Pirellis, going top with a 1m37.356s and then improving his pace to a 1m37.272s after a cool-down lap.
He resisted one challenge when Webber hit traffic on his first medium-tyre run.
But Vettel had no such dramas and a 1m36.733s lap put him comfortably on top.
Webber then got between the two Germans to take second with his final lap, which was 0.203 seconds off Vettel's pace.
Lewis Hamilton's Mercedes ultimately pushed Hulkenberg down to fourth.
Romain Grosjean turned the tables on new Lotus team-mate Heikki Kovalainen after the Finn's strong start on Friday, taking fifth to the newcomer's 13th. The pair were half a second apart.
McLaren had an encouraging session, as Jenson Button and Sergio Perez took sixth and eighth, split by Mercedes driver Nico Rosberg.
Williams also had reason to smile, with Valtteri Bottas beating Adrian Sutil to ninth.
Conversely Ferrari had a troubled morning, lacking pace on both tyre compounds. The best Fernando Alonso could manage was 11th place.
Pos Driver Team/Car Time Gap Laps 1. Sebastian Vettel Red Bull-Renault 1m36.733s 14 2. Mark Webber Red Bull-Renault 1m36.936s +0.203s 20 3. Lewis Hamilton Mercedes 1m37.064s +0.331s 22 4. Nico Hulkenberg Sauber-Ferrari 1m37.272s +0.539s 20 5. Romain Grosjean Lotus-Renault 1m37.345s +0.612s 20 6. Jenson Button McLaren-Mercedes 1m37.534s +0.801s 18 7. Nico Rosberg Mercedes 1m37.578s +0.845s 24 8. Sergio Perez McLaren-Mercedes 1m37.583s +0.850s 19 9. Valtteri Bottas Williams-Renault 1m37.747s +1.014s 17 10. Adrian Sutil Force India-Mercedes 1m37.748s +1.015s 21 11. Fernando Alonso Ferrari 1m37.763s +1.030s 16 12. Esteban Gutierrez Sauber-Ferrari 1m37.774s +1.041s 18 13. Heikki Kovalainen Lotus-Renault 1m37.879s +1.146s 21 14. Pastor Maldonado Williams-Renault 1m38.022s +1.289s 16 15. Daniel Ricciardo Toro Rosso-Ferrari 1m38.109s +1.376s 23 16. Paul di Resta Force India-Mercedes 1m38.275s +1.542s 22 17. Felipe Massa Ferrari 1m38.408s +1.675s 17 18. Jean-Eric Vergne Toro Rosso-Ferrari 1m38.636s +1.903s 21 19. Charles Pic Caterham-Renault 1m39.578s +2.845s 19 20. Giedo van der Garde Caterham-Renault 1m40.056s +3.323s 21 21. Jules Bianchi Marussia-Cosworth 1m40.825s +4.092s 21 22. Max Chilton Marussia-Cosworth 1m41.293s +4.560s 18