Oscar Piastri was left baffled as to why his McLaren suffered a sudden lack of grip in the final phase of qualifying for the Mexico City Grand Prix.

Piastri appeared on course to challenge for pole position in his MCL60 around the Autodromo Hermanos Rodriguez, with the Australian second quickest at the end of Q1, and in the same position after the first run in Q2.

Although the 22-year-old had dropped to fifth after the second run in the middle qualifying stint, the belief was he would again challenge in the top-10 shoot-out, only for that to fail to materialise.

Starting from seventh on the grid, asked by Speedcafe why his session had slipped away, Piastri said: “The car felt good through Q1 and Q2, and I had saved a set of tyres for Q3.

“But during that session, I didn’t have good grip for whatever reason. We’re still working out why. We had a bit of a similar thing in FP3, so we’re not 100 percent sure. I just didn’t find the time when everyone else did.

“It wasn’t the best lap I’ve ever done, the first lap in Q3, but I was very surprised when I was nine-tenths off, so still some things to look at from that aspect. It  was a shame because we were looking strong at that point.”

There were fluctuations in performance up and down the grid, the most notable being the pace of the Ferraris in Q3 as Charles Leclerc beat Carlos Sainz to pole after suggesting in Q1 and Q2 that a front-row lock-out was not on the cards.

In Q2, Mercedes duo Lewis Hamilton and George Russell were first and third quickest, only to fall away in Q3, leaving them to start sixth and eighth, either side of Piastri

Offering a possible explanation as to why the performance of a number of cars yo-yoed throughout, Piastri said: “It’s a combination of things. With the altitude, it’s very low downforce and it’s very easy to turn a small mistake into a big one.

“Also, the nature of the track, there are a lot of slow corners and corner sequences that can make it look even more costly when you make a mistake.

“In Q3, I think the track probably got a bit worse. With the last lap, I don’t think anybody really improved much.

“So yeah, just a combination of things, but the fact we have so little downforce around here always exacerbates your mistakes.”

The one driver who bucked the trend was fellow Australian Daniel Ricciardo in his AlphaTauri.

Ricciardo was remarkably consistent throughout, finishing third, fourth, and fourth quickest across each of the three sessions respectively.

Piastri at least acknowledged the performance of his compatriot, stating: “Daniel did a great job. He’s looked quick all weekend.

“He got it together, put a good lap together. I’m happy for him.”