Sainz was imperious in the pole shootout, setting two laps quick enough for top spot to put his and Ferrari’s supremacy around the high-altitude, low grip circuit beyond doubt.
“It’s very sweet because, it’s not normal to have such two strong laps around Mexico,” he said of the peculiar circuit. “It’s very difficult to put a lap together, and actually my two laps of Q3 were almost both perfect.
“I’m very happy to be on pole and to confirm the good form from Austin.”
After the Italian team dominated last weekend’s United States Grand Prix, Sainz in top spot with teammate Charles Leclerc in fourth gives Ferrari a golden chance to move past Red Bull Racing for second in the constructors championship and chart a course for McLaren in the lead.
“I’m relatively confident because I know my race pace should be good tomorrow,” he said. “Probably the biggest difficult thing will be the run down into turn 1 and starting on pole with a slipstream, but I think you can still defend, you can still make it stick into turn 1 starting on pole, and that will be my target tomorrow.”
Title leader Max Verstappen will start second after a strong recovery from a disrupted Friday that saw him complete just four untimed laps in FP2 owing to a power unit problem.
A new motor was bolted into the back of his Red Bull Racing machine for Saturday, and though he had his first Q3 lap deleted for exceeding track limits, perfect execution thereafter earnt him an unlikely front-row start.
“Yesterday I did four laps… so it was basically just a complete write-off,” he said. “I knew that it was going to be a tough qualifying, but we made some final adjustments; it all started to feel better, but to be on the front row is an incredible result for us.”
Perhaps most dangerous, however, will be Lando Norris starting from third, who will benefit from Sainz’s slipstream on the 890-metre run from the grid to the first braking zone, the longest launch in Formula 1.
Three of the last four winners of this race have started from third on the grid.
“If we can have a good start, hopefully it’s exciting down to turn 1,” he hedged. “Carlos is going to be fast. He’s got nothing to lose, and they’ve been fastest for the last few weekends.
“We’ll try our best, but I don’t think we have the pace comparing to them at the minute.”
Leclerc starts from fourth after an out-of-sorts weekend for the usually rapid Monegasque, though he was far more confidence of his race pace ahead of today’s 71-lap grand prix.
Mercedes duo George Russell and Lewis Hamilton weren’t in the pole mix but qualified fifth and sixth ahead of an excellent Kevin Magnussen in seventh for Haas.
Pierre Gasly and Alex Albon will scrap for crucial minor points in the backmarker battle between Alpine and Williams respectively, while Nico Hülkenberg made it two Haas cars in the top 10.
RB teammates Yuki Tsunoda and Liam Lawson had the pace for the top 10 but missed out when the former crashed out of Q2 with seconds remaining on the clock. Both drivers were on improving laps when the session was suspended, leaving them 11th and 12th respectively.
Fernando Alonso and Lance Stroll followed for Aston Martin in 13th and 14th ahead of Valtteri Bottas and Franco Colapinto.
Oscar Piastri was a shock Q1 elimination after a scrappy performance. His first lap on softs saw him lose time running off the track, which anyway resulted in his time being deleted, and his second, set on used tyres, was too slow to progress.
The Australian had topped final practice and expected to vie for pole but will start 17th instead, one year after Norris started form the same position at this track and finished fifth.
But the biggest disappointed was saved for the under-pressure Sergio Pérez, who will start 18th for his home grand prix in his worst qualifying performance since the midseason break.
The Mexican lamented that he couldn’t attack the slow corners, his laps riddled with lock-ups and wide slides that left him almost a second slower than teammate Verstappen and ahead of only Esteban Ocon and Zhou Guanyu on the grid.