Both Oscar Piastri and Lando Norris spent much of the session down the order after several moments on the slippery street circuit, allowing rival teams to capitalise on what may be a rare off-weekend for the Woking squad.

Norris ended the session sixth, two places ahead of Piastri, as Charles Leclerc took advantage of McLaren’s early struggles to top the timesheets with a 1m34.802s.

The Ferrari driver finished 0.166s ahead of an impressive Alex Albon for Williams, with the Red Bull pair of Yuki Tsunoda and Max Verstappen completing the top four.

Carlos Sainz backed up Williams’ strong pace in fifth, with Isack Hadjar seventh, followed by the Mercedes duo of George Russell and Kimi Antonelli in eighth and ninth. Lewis Hamilton completed the top 10 in the second Ferrari.

With temperatures dropping rapidly as the sun went down, drivers were met with a dirty track and slippery conditions, leaving many struggling for grip.

Leclerc improved steadily throughout the session, setting his fastest lap on medium tyres — the preferred compound for most of the field.

Verstappen briefly went quickest with a 1:35.109 before Tsunoda beat him by 0.038s, only for Leclerc to ultimately reset the benchmark.

McLaren split their approach, with Piastri running a lower-downforce rear wing while Norris tried a higher-downforce setup to suit the slower corners.

Both McLaren drivers had offs during the 60-minute session. Norris ran wide twice at Turn 11, appeared to struggle under braking, and earlier clipped the wall with his right-rear — prompting McLaren to check the car mid-session for damage. Piastri also ran wide at Turn 14 but continued without issue.

The session underlined the challenge of braking on Las Vegas’ abrasive surface. Norris and Piastri’s issues were compounded by apparent braking concerns, with the Brit frequently questioning his team over radio.

They weren’t alone in pushing the limits. Fernando Alonso and Oliver Bearman also visited run-off areas, while Hamilton produced several narrow escapes — including a spectacular save at Turn 12, drifting his Ferrari before recovering it cleanly.

Albon ended the session in the Turn 11 run-off after a lock-up, Liam Lawson went deep at Turn 14, and Pierre Gasly suffered an early spin at Turn 12 while probing the grip levels.

Cars return to the Las Vegas Strip Circuit for FP2 at 8pm local time (3pm AEDT).