Max Verstappen was left still searching for improvements after topping both practice sessions for the Mexico City Grand Prix.
The Dutchman's quickest lap was set during FP2 on a 1:18.686, which was 0.119s clear of McLaren's Lando Norris ensuring he topped both practice sessions have gone fastest in the opening 60 minutes.
Verstappen's Friday double comes after his victory in the United States Grand Prix, which was his 15th of the season as he seeks to break his own record by claiming a 16th win of the year this weekend.
He won the hard way in Austin after having his best qualifying lap deleted for track limits, but despite no such concerns in Mexico, he was left wanting to dial out oversteer that affected the RB19.
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Verstappen: Very close over one lap
In between FP1 and FP2 there was a temperature rise, with spots of rain also briefly hitting the circuit in the opening stages of the second session.
The Red Bull driver still feels there is more time to be extracted at the high speed circuit, which focuses on a low drag setup.
“There are a few things that can be improved," Verstappen reflected.
”But it's a positive start to the weekend, it is actually better than we expected, so that's not bad.
Verstappen expects lap times to be close in qualifying, based on the times set on the Soft tyre during FP2.
"The track is very slippery, as it always is here, and the tyres are difficult to manage in the long run, so there are still some things we need to work on.
"During qualifying, it will be very close over one lap, but the race pace is a different story."