Sebastian Vettel led a Ferrari 1-2 during a dry final practice session for Formula 1’s US Grand Prix, with Lewis Hamilton a close third.
Drivers maximised the dry and cool conditions at the Circuit of the Americas in the wake of persistent heavy rainfall limiting running on Friday.
Vettel, who faces a three-place grid penalty after a red flag transgression in FP1, set a time of 1:33.797 on the Ultrasoft tyres, leaving him just 0.046s clear of Ferrari team-mate Kimi Raikkonen.
Mercedes, having triumphed at the past four Grands Prix, was off the pace for much of the session, with Hamilton making a couple of mistakes on his push lap.
But Hamilton drew to within just 0.073s of his sole title rival on his final effort of the session.
Valtteri Bottas remained adrift in fourth place, seven tenths down on Vettel, with his Supersoft effort proving quicker than his Ultrasoft lap.
Red Bull took fifth and sixth, with Max Verstappen in front of Daniel Ricciardo.
Charles Leclerc led an ultra-close midfield group in seventh position, with just two-tenths of a second covering the Sauber driver, Sergio Perez, Carlos Sainz Jr., Romain Grosjean and Esteban Ocon.
Pierre Gasly was 12th for Toro Rosso, in front of Kevin Magnussen, Nico Hulkenberg and Marcus Ericsson.
Williams pair Lance Stroll and Sergey Sirotkin were next up, while Brendon Hartley split McLaren duo Stoffel Vandoorne and Fernando Alonso at the back of the pack.
Hartley was the only driver to have a major moment as he spun through Turn 19 late on.
Qualifying will begin at 16:00 local time
