Verstappen and Red Bull had looked comparatively out of sorts for most of the weekend, there or thereabouts but not topping any of the practice sessions on the way to qualifying.
And when Sainz was fastest in both first and second qualifying, the Spaniard looked a favourite for pole, just 15 days after having an operation for appendicitis that forced him to miss the Saudi Arabian Grand Prix.
But two exquisite laps from Verstappen in the final session were too good for the Ferraris and the Dutchman took his third pole position in a row this season, one he has started in even more dominant style than his record-breaking 2023.
“A bit unexpected in qualifying today but very happy with Q3,” Verstappen said. “Both of those laps felt very nice. Bit of a tricky weekend but we managed to be there at the end.”
Red Bull typically have an even greater advantage in the race than in qualifying but Ferrari’s long run in second practice looked strong and Verstappen said he was expecting a challenge in the race.
“They seem very quick also in the long runs so a bit of a question mark also for tomorrow but that makes it interesting,” he said.
It was a momentous performance from Sainz, in remarkable form considering he was just two weeks out from abdominal surgery.
He said: “It has ben a tough couple of weeks, a lot of days in bed, waiting to see if I could be here today. To make it this weekend and put it on the front row after leading all the way through qualifying, I almost could not believe it.
“Very happy to be here. I was a bit rusty yesterday but I got up to speed and feeling good with the car.
“I am not going to lie, I am not in my most comfortable state when I am driving out there but I can get it done. A lot of discomfort and weird feelings but no pain so it allowed me to push flat out.”
Perez took third in qualifying, 0.359secs slower than team-mate Verstappen, but was later given a three-place grid drop for impeding the Haas of Nico Hulkenberg in the first part of qualifying.
Leclerc had looked competitive on Friday but he said he felt the car had gone away from him on Saturday, developing understeer, and he had a “messy” qualifying as a result, adding too much front wing for the final run and generating oversteer instead.