While Daniel Ricciardo qualified a surprise fourth, Gasly is only 11th on Sunday's grid, while his team-mate Esteban Ocon struggled even more and couldn't better 16th in Q1, before gaining a spot from a grid penalty for Yuki Tsunoda.
Gasly, who drove for Toro Rosso/AlphaTauri in Mexico City five times between 2017 and 2022, suggested that the Faenza team has a very specific approach to the track, one that gives it a benefit over rivals, with data suggesting that while the AT04 was lacking compared to rivals on the straights, it is particularly strong in corners.
"[I'm] just disappointed with the overall performance of the car because we have just been not performing compared to all the guys we are fighting with usual," Gasly said of his qualifying session.
"I have my ideas on why we're not competitive and why AlphaTauri is competitive, for example."
Asked to expand, he said: "I won't comment on that. But there are a couple of obvious things and stuff that I've already told the guys, which cost us in Sector 1.
"It's stuff that even you can spot from onboard. You guys watch onboards, and you understand quite easily."
Asked by Motorsport.com to explain what his former driver had meant, AlphaTauri chief race engineer Jonathan Eddolls confirmed that the team did have a special focus on the Mexico City circuit.
"We always look at the characteristics of the track," said Eddolls. "And we do that every week, every event, but there are certain events where we come with let's say, a baseline set-up that's a bit different to normal. So a Monaco, a Singapore, or Baku in particular.
"And here, and I guess over the years, it seems that the car mechanically is very good. So everyone's struggling with grip, so if you've got a good car, mechanically, that helps.
"And as I say, with our aero package here, yeah, we haven't quite got the efficiency of some of the others but for this track, we've got the load in the corners. And it does suit this this event but yeah, we do come here with some of this a bit standout."
He added: "Just various things on the mechanical side, really, mainly on the mechanical side."
Eddolls acknowledged that the Honda power unit is also very effective in Mexico.
"I think that the Honda engine does seem very strong, even at altitude," he said. "I'm sure all teams are losing some performance compared to if we were racing this track at sea level but we're talking quite small numbers with Honda.
"I can't speak for others. But the Honda engine we know is strong, [and has] good driveability. And I think it manages these altitudes well."
Eddolls remains confident that Ricciardo can put in a strong performance in the race.
"The good thing is we've got a car that's obviously quite quick in the sections where there are corners," he said. "So the hope is that does keep the tyres alive.
"People are talking it's between a one and a two stop here. So if you can keep the tyres alive and make the one-stop work – I think we're in good stead when we look at the qualifying lap, compared to even [Max] Verstappen and [Charles] Leclerc.
"The only place he lost any time was up to Turn 1, from there on, he was nearly the same as the other two."
