Sergio Perez revealed braking issues were behind his painful Q1 elimination at his Mexican Grand Prix home race.
Perez only managed the 18th-fastest time in Q1 at the Autodromo Hermanos Rodriguez, missing the cutoff by two-tenths and joining McLaren driver Oscar Piastri in the drop zone.
The Red Bull driver had been struggling all weekend with the front of his RB20 and unresolved braking issues, which made him unable to attack corners.
"I've been struggling quite a bit with braking. Every time I try to attack the braking, I just put too much energy through the tyres and that makes it very tricky for me to stop the car," he said.
"It's been there for the last three races where I cannot stop the car. I'm having to modulate my braking quite a lot and that's something we can see in the data, but we are not able to fix it at the moment. It's mainly on the straight line I cannot stop the car. I just slide too much and given that it's all surface sensitivity here, it makes it a lot harder."
Perez crashed out of the race at the first corner last year and is desperate for a morale-boosting result in front of his home fans after a tough run of results.
But with his braking issues also occurring on longer runs, Perez is pessimistic about his chances of a strong comeback race. Given the severity of his handling issues, it is not out of the question the team may opt to make parc ferme changes and let him start from the pitlane instead.
"We will discuss all the options," he said. "The problem is that we are also very tight on parts that we have available. We don't have the spec of floor that we would like to go on to. I don't know, we will discuss it for sure with the team.
"It's going to be hard because it's also present there in the long run, so I will try everything. I will try and see what we are able to do with the team and see what solutions we are able to find.
"It's obviously very disappointing. If there's a grand prix that I want to do really well, it's this one. Unfortunately, this event has been really difficult and tricky."