Carlos Sainz led team mate Charles Leclerc in a Ferrari one-two in first practice for the Mexico City Formula One Grand Prix on Friday.
The Spaniard lapped the Autodromo Hermanos Rodriguez with a fastest time of one minute and 20.707 seconds with Monaco’s Leclerc 0.046 slower.
Both championships have already been won by Red Bull’s Max Verstappen and his team but Sunday’s high-altitude race will see the Dutch driver and team mate Sergio Perez each chasing their own first.
Perez can become the first Mexican to win his home race while Verstappen will be chasing a record 14th win in a single season as the team move on from being punished for breaching last year’s cost cap.
Both recorded exactly the same lap time, 1:20.827, but the home favourite was third on the timesheets because he set it first. Verstappen also spun but managed to keep his car out of the barriers.
Seven-times world champion Lewis Hamilton, still chasing his first win of the season with three races remaining, was fifth fastest with two-times champion Fernando Alonso sixth for Renault-owned Alpine.
The session saw several young drivers on track, including Australian Jack Doohan -- son of motorcycling great Mick -- at Alpine.
The 19-year-old’s practice debut was cut short, however, with the team concerned about the power unit in the car Esteban Ocon will race.
The red flags twice halted the session, once when Haas’s Brazilian reserve Pietro Fittipaldi had an engine failure and then at the end when New Zealand’s Red Bull junior Liam Lawson stopped with his AlphaTauri’s brakes on fire.
Williams had Logan Sargeant in their car again while Mercedes gave reserve Nyck de Vries, joining AlphaTauri next year, another run.
The second session will run for 90 minutes and include a Pirelli tyre test.