A surprised Charles Leclerc admitted he did not expect his success on Saturday after he secured pole position ahead of team-mate Carlos Sainz as Ferrari locked out the front row for Sunday's Mexico Grand Prix.

In a chaotic and confusing qualifying session that seemed set to see Max Verstappen on pole again, Ferrari emerged in Q3 with a surge of pace that surprised almost everyone.

The Monegasque clocked a best lap in one minute and 17.166 seconds to beat the Spaniard by 0.067 seconds, leaving newly-crowned three-time world champion Verstappen third for Red Bull.

"It's two weekends in a row where we say that we don't know if we have the pace," said Leclerc. "People will start not believing us anymore! To be honest, I did not expect to be on pole today -- I thought we were lucky after FP3.

"But once we put everything together it all went well. The new tyres gained a lot, but I am already focusing on tomorrow's race. We may have pole position, but now we need to convert it into a win and obviously it is going to be very difficult."

Sainz admitted: "It was a strange one. This whole weekend I've struggled to put a lap together then the first lap I put together in Q3 was P1 and suddenly Charles beat me by half a tenth, one tenth...

"I'm just struggling to understand where we can find half a second -- and then we go half a second slower in the next lap. It's very tricky with the tyres.

"The feeling with the car is very strange around this circuit, but we managed to put a good lap in when it counted," he added.

Verstappen, who will be hunting a 51st career win in Sunday's race, said: "It's very difficult here.... It's very low grip around here because of the altitude so when you try and push a little bit more it goes a bit away from you.

"We're very close and it's a very long race with a lot of laps to be raced. Of course, I would have liked to start first, but we'll have a good slipstream into turn one so we'll see what happens."

After dominating all three practice sessions, it was a surprise to see the 26-year-old Dutchman unable to stay on top as Ferrari found a surge of additional pace in the final Q3 section of qualifying.

Daniel Ricciardo was fourth for Alpha Tauri ahead of local hero Sergio Perez in the second Red Bull, seven-time champion Lewis Hamilton of Mercedes and Oscar Piastri of McLaren.

George Russell was eighth in the second Mercedes ahead of the Alfa Romeo pair of Valtteri Bottas and Zhou Guanyu.

Three of the top ten -- Verstappen, Hamilton and Russell -- faced stewards' investigations for infringements during qualifying, Hamilton for ignoring yellow flags and Russell and Verstappen for holding up the field in the pitlane.

It is Leclerc's fourth pole position success this year and the 22nd of his career, but he is without a win this season and has struggled to convert poles to wins. His last victory was at the 2022 Austrian Grand Prix, the fifth of his career.