Two-time F1 champion Max Verstappen was able to laugh off a spin midway through a first practice session for the Mexico City Grand Prix that was twice red-flagged.
Ferrari's Carlos Sainz led the way at the end of an eventful hour at the Autodromo Hermanos Rodriguez with a lap of one minute 20.707secs, finishing 0.046s clear of team-mate Charles Leclerc.
Red Bull duo Sergio Perez and Verstappen finished equal on time of 1:20.827s, with the Mexican on home soil ahead of the Dutchman by virtue of the fact he posted his time first.
Verstappen would arguably have gone quickest after posting a purple first sector, only to spin emerging out of the compression at turn 10, one that left the 25-year-old chuckling over the team radio and complaining of no grip.
For the rookies on show, it was a difficult session.
Just as marshals were pushing Zhou Guanyu's Alfa Romeo back down the pit lane after he had stopped at the end of it, Pietro Fittipaldi brought out the red flags for the second consecutive FP1 involving Haas with 23 minutes remaining.
A week ago ahead of the United States Grand Prix, it was Antonio Giovinazzi who brought proceedings to a halt via a crash.
At least there was nothing as embarrassing for Fittipaldi - taking over the car from Kevin Magnussen - as the Brazilian was ordered to stop due to an issue with the Ferrari power unit.
Magnussen, however, will face a grid penalty as team principal Guenther Steiner confirmed a new PU will be required.
Alpine's Jack Doohan, in for Esteban Ocon, also had to stop as a precaution due to the team seeing anomalies with the PU data.
In the closing minutes, the brakes on Liam Lawson's AlphaTauri caught fire, forcing him to stop on track and bringing out the red flags and an early end to FP1.
Lawson, Doohan and Fittipaldi finished 16th, 19th and last on the timesheet, albeit all were on the hard tyres, as were the other two rookies in the session in Logan Sargeant for Williams and Nyck De Vries for Mercedes as George Russell made way.
In a nice touch, after the session had concluded, De Vries thanked Mercedes for his three years with them and ahead of his impending move to AlphaTauri over the winter as replacement for Alpine-bound Pierre Gasly.
De Vries' team-mate in seven-time champion Lewis Hamilton was fifth quickest, followed by Alpine's Fernando Alonso, with the top six covered by less than two-tenths of a second.
Alfa Romeo's Valtteri Bottas, Lando Norris in his McLaren, Gasly and Aston Martin's Sebastian Vettel completed the top 10, the latter 0.818s down, with Daniel Ricciardo next up, a second off the pace.
Mexico City Grand Prix first practice results
1. Carlos Sainz [Ferrari] 1:20.707
2. Charles Leclerc [Ferrari] +0.046s
3. Sergio Perez [Red Bull] +0.120s
4. Max Verstappen [Red Bull] +0.120s
5. Lewis Hamilton [Mercedes] +0.142s
6. Fernando Alonso [Alpine] +0.192s
7. Valtteri Bottas [Alfa Romeo] +0.376s
8. Lando Norris [McLaren] +0.413s
9. Pierre Gasly [AlphaTauri] +0.603s
10. Sebastian Vettel [Aston Martin] +0.818s
11. Daniel Ricciardo [McLaren] +1.055s
12. Zhou Guanyu [Alfa Romeo] +1.113s
13. Lance Stroll [Aston Martin] +1.158s
14. Mick Schumacher [Haas] +1.245s
15. Nicholas Latifi [Williams] +2.205s
16. Liam Lawson [AlphaTauri] +3.154s
17. Logan Sergeant [Williams] +3.539s
18. Nyck de Vries [Mercedes] +3.875s
19. Jack Doohan [Alpine] +3.908s
20. Pietro Fittipaldi [Haas] +6.059s