Lewis Hamilton topped final practice for the United States Grand Prix, giving Ferrari a clean sweep across all three sessions at the Circuit of the Americas (COTA).
The seven-time world champion set a fastest lap of 1:34.893, ahead of Red Bull's Max Verstappen, who did a 1:35.01, while Hamilton's teammate Charles Leclerc finished third with a time of 1:35.127.
The Mercedes duo of Kimi Antonelli and George Russell completed the top five, with Antonelli finishing fourth and Russell fifth. Oscar Piastri finished sixth and his teammate Lando Norris in eighth, underscoring the struggles that McLaren have had this weekend.
Audi's Nico Hulkenberg was seventh, splitting the McLarens while Pierre Gasly and Isack Hadjar finished ninth and tenth.
A test session feel to it
Cadillac's Sergio Perez was the first driver out on track, setting a time of 1:39.880 on the hard tyres. The leading teams were slow to emerge, with Hamilton among the first front runners to head out on track on the softs.
Verstappen quickly showed his pace on the mediums, briefly moving to the top of the timesheets. Antonelli moved to third on his first lap, but it was deleted due to track limits.
Verstappen again complained about his gear shifts, while Red Bull teammate Isack Hadjar also expressed his own frustrations on the radio. "I don't know where my car is. I don't know what's happening."
Drivers struggled with COTA's bumpy surface and the wind, with several cars snapping into oversteer.
Over 200 lap times were deleted across Friday's two sessions, and that trend continued across FP3 on Saturday.
Turn 12 proved to be particularly challenging, while turn 1 also caught several drivers out. Leclerc had two flying laps deleted, and his fastest one at that, for exceeding track limits. Norris also lost a flying lap on the soft tyres, while Antonelli was also among those exceeding the white lines.
After three sessions of similar problems, track limits remain a concern heading into qualifying.
The outlook for qualifying
Ferrari's head into qualifying in a strong position after topping all three practice sessions. Verstappen has been their closest challenger overall, despite constantly voicing frustration at his car.
The medium tyre also appeared to be competitive during the opening half-hour of practice, with most of the field using them in the early parts of the session.
A front runner like Ferrari, who have done so in the past, could take the gamble and use the mediums in Q1, but it remains to be seen whether the tyre can keep pace with the softs on lower fuel loads.
All the top teams look evenly poised, but Ferrari's pace gives them reason for confidence. Verstappen remains close by.
With track limits continuing to catch drivers out, a clean lap could prove to be decisive for pole.
