Ferrari and Alpine struggled to cope with the thinner air throughout the Mexican GP weekend.
At the fabled Autodromo Hermanos Rodriguez in Mexico City, the altitude is 2,238 - meaning much thinner air for the aerodynamics but also the power units.
It emerged over the course of the weekend that Ferrari's struggles for pace may be connected to rumours that performance of the turbocharger - notably smaller than some other F1 designs - had to be 'turned down' to cope.
To compensate, Ferrari had to reduce downforce.
"I'm almost sure there is a problem," Charles Leclerc told the French broadcaster Canal Plus.
"We were losing a lot of time on the straight, not only compared to Mercedes and Red Bull but there is something weird about the straights.
"Then when you pick up the throttle out of a corner, there is something wrong."
Carlos Sainz, however, insisted that Ferrari "understands why we are going slowly and what compromises we have to make", even though the actual pace was "even more difficult than we expected".
Leclerc continued: "We found ourselves in a lot of difficulty, especially on the engine side. One minute behind is really a lot and it hurts.
"Engine wise, we couldn't change what we wanted to change, but it still doesn't explain the gap."
It is believed Sainz's turbocharger actually sustained damage throughout the weekend, with team boss Mattia Binotto declaring: "I'm not ruling out a penalty for Sainz for changing power units in Brazil".
He told Sky Italia: "We have no explanations, but it is a race that must be analysed as we needed these races for the future.
"We suffered with the power unit, but also with the car. And I don't have a certain answer to that."
Also struggling with the altitude in Mexico was Alpine, whose Fernando Alonso confirmed that the team worked on cooling "more than anything else".
"We had to make several changes for the car to survive the race," said the Spaniard. Ultimately, however, his engine failed - and Alonso could not hide his frustration.
"The truth is that this year has been a bit strange with all the points we have lost. I was on 5 cylinders for 20 laps, making a bit of a fool of myself, and finally it broke which was for the best.
"Again, just car 14, as usual," he told the DAZN broadcaster. "I wanted to stop for a long time but the team wanted to see if by a miracle we could stay in the points."
Indeed, Alpine is trying to fend off McLaren to secure fourth overall in the constructors' championship.
"There are two races left to enjoy with them and it is the team of my history in F1, Renault, and the team that gave me the opportunity to return to this sport last year as well," said Alonso.
"So yes, I'm going to help them until the last lap."
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