Max Verstappen rued "useless" Friday practice at Formula 1's Mexico Grand Prix, following a series of power unit issues that hampered his running throughout the day.
Verstappen reported there was "something wrong" with his engine at the end of FP1, which caused him to miss the final five minutes of running in the opening hour-long session.
This persisted throughout FP2, which was dedicated to testing Pirelli's prototype tyre compounds for 2025, as Verstappen reported there was a "weird noise" emanating from his power unit - which he later described as "very disturbing" over the radio.
This prompted the team to bring his car back to the garage, and he did not return for the rest of the session after just four laps of running.
Regardless, Verstappen reckoned that he wouldn't need to serve a grid penalty in Mexico to change any power unit components, simply chalking it up as a "day to forget".
"From the engine side we are checking, I don't know exactly what it is," Verstappen said after the session. "But yeah, from my side [it was] a pretty much useless day. I did like four or five laps, and that's not much to read into.
"It'll be alright [without a penalty]. I never really had a good run. I did four or five laps in total and that's even with some long run laps in it. So a day to forget."
Red Bull adviser Helmut Marko told Austrian broadcaster ORF that this was a recurring problem, which the team believed had previously been fixed.
He agreed with Verstappen that it was not likely to require any new power unit components that carried a penalty, and that the nature of FP2 lessened the blow to his run plan.
"It's the same problem, and we're in the process of finding out why it's come back, even though it's been fixed. It's not a serious problem, it just needs to be solved. There is a leak somewhere," Marko said.
"[We only did] two timed laps with Max [in FP1], and even those two timed laps weren't at full power. So it's going to be difficult, so thankfully this second practice session was on control tyres and we weren't allowed to change anything, so the damage is limited."
Verstappen was classified 19th without a time to his name in FP2, while Alex Albon did not run at all during the 90-minute session as Williams was still fixing the extensive damage to his car after an FP1 clash with Ferrari reserve Oliver Bearman.
