Max Verstappen headed Lando Norris at the end of a second practice session in Mexico City that took place under the threat of rain.
Verstappen’s best came midway through the hour-long outing as teams performed qualifying simulations, the Red Bull driver 0.119s faster than his McLaren rival.
Aside from the single lap runs, the medium tyres were the favoured rubber as Charles Leclerc ended the day third fastest with Valtteri Bottas a surprise fourth for Alfa Romeo Sauber.
Daniel Ricciardo meanwhile was sixth best, with McLaren’s Oscar Piastri ninth.
The risk of rain later in the session prompted a busy start with all but Max Verstappen and Alex Albon remaining in the garage as the pit exit opened.
Another encouragement was the prototype tyres available this weekend, affording teams the opportunity to perform additional running.
Seven minutes into the session, Verstappen reported light rain out on track.
That was despite the circuit basking in sunshine, the dark clouds that threatened had not yet reached the Autodromo Hermanos Rodriguez.
Conditions hadn’t deteriorated much, if at all, with Verstappen setting a best time of 1:20.085s.
The weather was closing in from the final complex; through the last corner and the stadium section which precedes it.
Cloud cover gradually enveloped the circuit, the pace having improved to 1:19.511s from Verstappen.
Daniel Ricciardo sat third fastest after 20 minutes, his time 0.2s away from the outright pace.
His time had come on a set of the prototype rubber – a 2024-development spec of the medium rubber – while Verstappen had used the current-sped mediums for his best.
Soon after, Oscar Piastri moved to the top of the timesheets with a time 0.463s faster than anyone else to that point.
It was a time that came on the soft compound rubber, the Australian was the first to begin looking at short-run performance.
Others soon followed, with Alex Albon, Sergio Perez, Lando Norris, and Fernando Alonso among others fitting the red-walled tyres.
A dramatic spin for Alonso at Turn 9 briefly drew the yellow flags, but the Spaniard was able to carry on without further incident.
The Spaniard lost the rear-end around the left-hander as he was pitched into a highspeed 360, after which he neatly gathered the car and carried on.
He was second fastest after his soft tyre run, a 1:19.446s behind Piastri.
Verstappen soon changed that order, with a 1:18.686s to return to the top of the timesheets while Lando Norris managed a 1:18.805s lap to sit second.
Others also improved as the order began to change with almost every car crossing the line.
By the midway point of the practice hour, the cloud that threatened to douse the circuit had largely passed over.
However, the threat of rain remained, prompting teams to head back out on track to complete race running.
Alex Albon reported rainfall with 17 minutes remaining, the Williams driver sitting 14th fastest after his qualifying simulation run.
It was notably darker though there were no plumes of spray despite rain falling, slicks still the correct tyre option.
On track, times were not a long way from what would have been expected as teams worked through their programmes in the latter stages.
The medium tyre was the preferred option, though some opted for hards – Ricciardo and Piastri among them.
Elsewhere, the Aston Martin pair of Fernando Alonso and Lance Stroll were just 20th and 18th, neither having managed a true qualifying run during the middle of the session, leaving them somewhat out of position.
Williams ended its session in the garage, an unusual choice given it meant they were unable to perform practice starts on the grid once the chequered flag fell.
A final hour of practice follows from 04:30 AEDT tomorrow (11:30 local time, Saturday).
