A red flag was triggered with around 21 minutes remaining after a loose manhole cover was discovered on the approach to Turn 17, halting the session for roughly 15 minutes while marshals carried out repairs.

Running resumed with just over five minutes left, prompting a frenetic rush of cars onto the circuit as drivers attempted to squeeze in a push lap on soft tyres.

But a second red flag for “track maintenance” arrived with two minutes remaining, ending the session prematurely.

With no meaningful soft-tyre running at the end, Norris’s earlier lap of 1m33.602s held firm at the top, a strong recovery after a difficult FP1 in which both McLaren drivers struggled for pace.

McLaren switched back to its Monza-spec rear wing for FP2, and while Norris immediately benefited, Oscar Piastri was unable to get a clean late lap on soft tyres due to the stoppages.

He ended the session 14th, though this was more a reflection of timing than outright speed.

Piastri had shown promising pace earlier as the surface improved, briefly slotting just under three-hundredths behind Norris before the Briton then improved on the softs moments before the first red flag.

Rain prior to the session left the circuit especially slippery early on, though cars ventured out quickly as grip levels gradually improved under the cool Vegas conditions.

Kimi Antonelli delivered an impressive run to go second for Mercedes, ahead of FP1 pacesetter Charles Leclerc.

However, Leclerc’s session ended early after a suspected gearbox failure. The Ferrari driver joined the late-session rush to leave the pits after the first red flag but immediately reported an issue, pulling over at Turn 5 and telling his team “something has broken” over the radio.

He also survived a big lock-up earlier in the session, narrowly avoiding the wall approaching Turn 9.

Nico Hulkenberg placed fourth for Sauber, followed by the Racing Bulls pair of Isack Hadjar and Liam Lawson. George Russell was seventh in the second Mercedes, while Alex Albon took eighth for Williams, edging Max Verstappen and Lewis Hamilton, who completed the top 10.

Multiple drivers had offs as the field continued to battle the low-grip surface, with Norris and Hadjar among those sliding wide into Turn 16.

Attention now turns to the final practice session, with teams hoping for an uninterrupted hour to properly prepare for qualifying.

FP3 in Las Vegas begins at 4:30pm local time Friday (11:30am AEDT Saturday).