Sainz leads Ferrari 1-2 as Verstappen spins in first practice
The time for F1 cost cap talk was over for 60 minutes as the first session of running at the Autodromo Hermanos Rodriguez got underway.
The low grip track conditions caught out a number of drivers, including two-time world champion Verstappen.
Verstappen was struggling with tyre grip in the middle part of the lap while running on the softs, losing control of his Red Bull and spinning at Turn 11.
He complained over team radio afterwards: "It's unbelievable. I couldn't correct it. So little grip."
Verstappen could only manage the fourth-fastest time, slotting in behind Sainz, Charles Leclerc and Sergio Perez.
It was tight at the top with just under 0.2s separating Sainz and Fernando Alonso in sixth.
Lewis Hamilton was one of the last drivers to set a lap on the softs, ending the session P5 overall.
Valtteri Bottas was just behind Alonso in seventh, while Lando Norris, Pierre Gasly and Sebastian Vettel rounded out the top 10.
Daniel Ricciardo was 11th overall after spending much of the session in the garage with a brake issue.
Next up was Zhou Guanyu, Lance Stroll, Mick Schumacher and Nicholas Latifi.
Liam Lawson was 16th, replacing Yuki Tsunoda for this session.
Lawson caused the second of two red flags, forcing the session to end early.
Logan Sargeant (in for Alex Albon) was 17th overall ahead of Nyck de Vries (replacing George Russell).
Jack Doohan’s session was cut short due to “anomalies in its PU data.” - ending the day 19th.
Pietro Fittipaldi completed the order but a power unit issue halted his session early on.
