The McLaren driver ran off the road in the final sector in the dying moments of Qualifying 3, ruining what was his only timed lap of the segment.

It left him 10th fastest, officially without a time, though he will line up ninth on the grid after Sergio Perez takes a three-place grid penalty.

“It wasn’t looking amazing; it certainly wasn’t going to be pole,” Piastri said of his final lap.

“I don’t feel like I threw away that much of a result.

“Honestly, I think it would have been maybe P7 or P8 at best, so I don’t feel like I’ve made a mistake that’s cost a big result.”

Piastri has been half a step behind team-mate Lando Norris throughout the weekend in Spain.

The Englishman snagged pole position ahead of Max Verstappen at the chequered flagged waved.

Norris recorded a Qualifying 3 best of 1:11.383s, while Piastri’s best came at the end of Qualifying 2, when he logged a 1:12.011s.

McLaren had opted to send Piastri out for a third run in Qualifying 1, which cost him a set of tyres and ultimately compromised his ability to record a banker lap early in Qualifying 3.

“It’s just not been very natural all weekend,” Piastri explained.

“In the last four or five races, from the first lap of practice, I’ve been able to be comfortable with the car and then push on from there.

“This weekend it’s not been coming.”

McLaren is one of four teams not to have any declared upgrades this weekend, a point Piastri note when trying to unravel the reasons for his struggle.

The difference between the McLaren pair in qualifying trim has been less than a second thus far in 2024, making them two of the most equally matched drivers over a single lap.

Piastri started on the front row in Monaco, and was similarly fast in Imola but a penalty for impeding saw him start fifth instead of second.

Clearly comfortable in the car elsewhere, it suggests his struggles this weekend are specific to the Spanish GP.

“Since we put the upgrades on, half of them in Miami and then the full set at Imola, it’s been really good to drive,” Piastri said of the MCL38.

“Imola in particular I felt very, very comfy from lap one, and the car’s not changed since then.

“This weekend, for whatever reason, has been more difficult. So nothing to do with the upgrades, just not clicked.

“It’s been a little bit random,” he added of the limitation he feels in the car.

“I think, for me, it’s kind of an indicator that [I’ve] just not had much confidence with the car.

“If it’s one or two corners consistently then you can kind of go ‘he’s doing a better job’, but one session has been one corner, the next one has been somewhere else.

“The last sector has been a little bit difficult, but never for the same reason.

“It’s just been very, very tough for me to find the limit.”

In qualifying, that resulted in Piastri simply pushing too hard and running off the track.

“My lap wasn’t going to be anything amazing at that point so I knew I didn’t really have anything to lose,” he recounted.

“Just got a massive push of understeer, I don’t know if I tried to carry a bit too much speed or had a gust of wind or whatever.

“But yeah, just not really been a very predictable day in terms of what the car’s going to do.”

The Spanish Grand Prix begins at 15:00 local time on Sunday (23:00 AEST).