Sebastian Vettel and Mark Webber led the way for Red Bull again in final United States Grand Prix practice, despite a star cameo from Nico Hulkenberg.
Friday pacesetter Vettel had taken 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 tires and qualifying simulations for the final few minutes.
It was Hulkenberg who 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-tire run. But Vettel had no such dramas and a 1m36.733s lap put him comfortably in first place.
Webber then got between the two Germans to take second with his final lap, which was 0.203 second off Vettel’s pace. Lewis Hamilton’s Mercedes ultimately pushed Hulkenberg down to a still-impressive fourth.
Romain Grosjean turned the tables on new Lotus teammate 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 tire compounds. The best Fernando Alonso could manage was 11th place.