Carlos Sainz led Ferrari teammate Charles Leclerc to the top of the time sheet in first practice for the Mexico City Grand Prix.

Sainz, pole-getter last weekend in the USGP at Circuit of The Americas, set a best time of 1m20.707s to best Leclerc by just 0.046s in a largely trouble-free session for the works team.

The same couldn’t be said for the Ferrari power unit, however, which failed in the back of Pietro Fittipaldi’s Haas car after just nine laps in a plume of smoke down the front straight.

Fittipaldi was sitting in for Kevin Magnussen in one of the team’s mandatory rookie runs when he was instructed to pull to the side of the track, causing a red flag with around 20 minutes to go.

The team suspects a turbocharger and MGU-H problem, a common occurrence for the Italian motor this season, particularly early in the year. The air is approximately 22 percent less dense at 1.3 miles above sea level, putting extra strain on the turbo to maintain pressure in the internal combustion engine.

Ferrari wasn’t the only motor to encounter troubles, nor Fittipaldi the only rookie. Jack Doohan, standing in for Esteban Ocon, had his session ended early by anomalous engine data from this Renault power unit, leaving him with just 13 laps in his F1 weekend debut. Liam Lawson then brought the session to an end around four minutes early with an ugly-sounding crunch from his AlphaTauri’s Honda motor as he entered the stadium section, forcing him to stop on track.

Liam Lawson's brakes were too hot to handle in FP1! 😱🔥#MexicoGP #F1 pic.twitter.com/4vp22ksCaZ

— Formula 1 (@F1) October 28, 2022

Sergio Perez’s Honda engine wasn’t so troubled, powering the home favorite to third in the order and 0.12s off the pace. His time was matched by teammate Max Verstappen, but the Dutchman set his time second after abandoning his first soft-tire run due to a mistake and his second run to a spin through Turns 10 and 11 that came perilously close to putting him in the wall.

Lewis Hamilton was fifth for Mercedes and 0.142s adrift, though his first soft-tire run had to be abandoned for Fittipaldi’s red flag. Fernando Alonso completed the top six for Alpine, the leading sextet split by just 0.192s.

Valtteri Bottas was seventh for Alfa Romeo ahead of McLaren’s Lando Norris and the sole surviving AlphaTauri of Pierre Gasly. Sebastian Vettel — in a special Red Bull tribute helmet dedicated to Dietrich Mateschitz — completed the top 10 for Aston Martin at 0.818s off the pace.

Daniel Ricciardo was 11th after a long layoff in his garage with brake problems, returning to the track with around 10 minutes remaining for his soft-tire run.

Zhou Guanyu was 12th despite his stoppage, ahead of Lance Stroll, Mick Schumacher and Nicholas Latifi.

The troubled Lawson was 16th ahead of 2023 Williams driver Logan Sargeant and Mercedes standout Nyck de Vries, who completed his last on-track duty for the German marque before he switched to AlphaTauri next year.

Doohan was 19th ahead of Fittipaldi at the foot of the table, after their engine problems.