George Russell completed a Mercedes practice clean sweep at the Las Vegas Grand Prix after a late red flag truncated the final qualifying preparations in FP3.
The frontrunners — bar Russell — had each completed one flying lap on fresh soft tire as the circuit began to grip up when Lance Stroll’s Aston Martin switched itself off exiting Turn 12, at the north end of Las Vegas Boulevard.
The Canadian parked by a gap in the fence, but the car’s warning lights suggested the hybrid system hadn’t been safely disabled and the car was therefore unsafe for the marshals to touch, necessitating a red flag to recover the stricken car from the track.
With less than seven minutes remaining on the clock, the stoppage effectively ended the session, with running resuming in the final 60 seconds only to allow for practice starts.
It ensured Russell, who was the only one of the leaders to have completed two flying laps, was locked into top spot with a best time of 1m 33.570s.
The benchmark was around 0.3s quicker than FP2 on Thursday and approximately half a second quicker than FP3 last seas on.
Oscar Piastri, the penultimate frontrunner to cross the line before the red flag, was second and 0.215s adrift, with Carlos Sainz making it three teams inside the top three by taking his Ferrari around the track 0.348s off the pace.
Lando Norris, the last of the top drivers to set a time, was fourth and 0.438s slower than Russell.
Max Verstappen completed a herculean turnaround for Red Bull Racing after having lamented a lack of one-lap pace at the end of Thursday practice, his RB20 struggling in the low-grip conditions.