Aston Martin 'fail moment of truth' after basic Mexico challenge 'underestimated'

Fernando Alonso believes Aston Martin and Honda "underestimated" their "moment of truth" test in Mexico City after power unit failures wrecked his weekend.

Despite believing his car could have challenged for a strong Q2 spot at the Autodromo Hermanos Rodríguez, Alonso was told to stop after just one flying lap in qualifying, with a water pressure issue. 

New parts were fitted for the race, but both Alonso and team-mate Lance Stroll retired after just five laps with what the team called "abnormal pressure levels in the PU systems."

A key challenge of the weekend was dealing with the altitude of Mexico City, which is 2,285m above sea level, and where air density is around 20% lower than at sea level. 

This meant the turbos had to work harder to provide the demanded power by drivers, but with the removal of the MGU-H from the 2026 power units, a crucial tool in eliminating turbo lag was also taken away, to add to the challenge.

Reflecting after a promising round of practice sessions, including FP1 where Alonso's seventh best was Aston Martin's best result in any session all season, the two-time champion felt the car had failed its ultimate "moment of truth" test and that the altitude challenge had been "underestimated."

"We did as much as we could [in trying to protect the power unit], but Mexico always provides very big challenges for the power units, and even with that, it seems that it was not enough, so we had to retire the car," Alonso told media, including RacingNews365. 

"Two short laps in qualifying, and the race is very frustrating because the three free practices were fine - we did a lot of laps in FP1, FP2, and FP2.

"And then when we got to the moment of truth in qualifying and the race, we didn't manage to do enough laps.

"But this is part of the process of learning, and hopefully we can learn hard lessons and learn things from [this weekend]."

Turning to his retirement, Alonso then added that he knew it was a "shared problem" with Stroll when the sister car retired, before adding that he felt "the challenge with the altitude was probably underestimated by the power unit."