Norris topped the timesheets with a 1m33.294s, edging out a surprising Nico Hulkenberg for Sauber, while teammate Oscar Piastri finished two tenths back in third.

Hulkenberg, who has an impressive record at the Circuit of the Americas, looked strong throughout the session and fired himself up to second at the death, setting the fastest middle sector of anyone in the process.

Piastri, meanwhile, also vaulted up the order late, finding pace in his McLaren once he switched to the soft tyres as the track rubbered in under the hot Texan skies.

While the top three led the way, Ferrari will once again be working hard to find some pace, with Lewis Hamilton down in eighth and Charles Leclerc anchoring the bottom of the timesheets.

Leclerc reported a smell of burning oil in the cockpit and was told to pit immediately by Ferrari, the Monegasque driver emerging from his car to sit out the remainder of the session, leaving his team with plenty of work to do ahead of Sprint Qualifying.

Hamilton’s lap in eighth came on the medium compound tyres and was only four hundredths slower than George Russell in seventh, with both Mercedes drivers choosing not to run the softs during the only practice session of the weekend.

It was a relatively incident-free hour of running, with a brief red flag to clear debris from Lance Stroll’s Aston Martin the only interruption. Stroll finished 14th, while his teammate Fernando Alonso backed up his impressive FP1 form from Singapore by finishing fourth.

Max Verstappen was fifth for Red Bull, showing strong pace early on as teams adjusted to the hot Austin conditions. Verstappen’s teammate Yuki Tsunoda also looked lively in the opening stages, running in the top two alongside Verstappen for much of the session before eventually dropping to 13th.

The Japanese driver had a heart-in-mouth moment near the end when his Red Bull snapped into the runoff through the fast opening chicanes, seemingly after hitting a bump, though he managed to catch the slide and continue.

It was a mixed session for Williams, with Alex Albon finishing sixth while Carlos Sainz spent most of the hour in the garage with an apparent gearbox issue. Sainz was told to pit immediately once the issue was detected and “not to push,” the Spaniard looking visibly frustrated as he stepped from the car.

Isack Hadjar was another driver left frustrated, engaging in several heated exchanges with his engineer over the radio and reporting a car issue late in the session. Despite that, the Frenchman still finished ninth, one place ahead of the Haas pair of Oliver Bearman and Esteban Ocon.

Ocon had a moment heading into the hairpin midway through the session, running straight on into the gravel before reporting a throttle issue over team radio.

Gabriel Bortoleto was 12th for Sauber, with Liam Lawson down in 15th for Racing Bulls. The Alpine duo of Franco Colapinto and Pierre Gasly finished 16th and 17th respectively, while Kimi Antonelli couldn’t replicate his teammate’s pace on medium tyres, ending up 18th.

Cars return to the track later today for Sprint Qualifying at 4:30pm local time (8:30am AEDT).