After building his title lead from 14 to 65-points over the previous five races, stretching back to the incident with his leathers in Barcelona, Fabio Quartararo's world championship advantage was pegged back to 53 points by an eighth place finish at Aragon.

The Monster Yamaha rider confessed prior to the weekend that the Spanish circuit was probably his worst of the season, but still qualified on the front row and fully expected to fight for the rostrum.

Instead, he suffered a 'strange' lack of rear grip from the start of the race and dropped back to a low of tenth place by mid-distance, before fighting back past the Ducatis of rookies Enea Bastianini and Jorge Martin.

"I expected to be fighting for the podium after warm-up because I was feeling great and with 26 laps on the tyre [3 more than the race distance] I could manage great," Quartararo said.

"But from the start of the race I felt like my rear tyre was not working as normal. I went down, down, down. The only positive thing of today is that I fought for my position and I didn’t give up. It was only for 7th, 8th and 9th but I went for it until the end."

Quartararo had suffered a similar, if more dramatic, decline in last year's Aragon race, when his front tyre pressures rose too high while in the slipstream of other riders.

The Frenchman insisted tyre pressure had not been a factor this time around and, although he didn't want to blame Michelin, it was clear that some form of tyre performance issue - of the kind suffered by title rivals Francesco Bagnaia and Joan Mir in previous races - was top of his suspect list.

"Today something went wrong. Last year everything was normal apart from the mistakes on the front tyre [pressure]. I don’t know what happened today but from the first laps it looks like my rear tyre... We need to check deeply and I don’t want to blame nothing, but it was a weird feeling from the first laps until the end of the race.

"I don’t want to say it is the tyre, but the feeling I had today I never had it in all the weekend and straight away from the first lap I did not have the stopping performance I had [previously], not the grip, not the traction.

"Also for us to overtake on that track is quite a mess because from Turn 15 to Turn 1 we lose 3-4 tenths and I need to recover on the corners and then I can’t overtake. It is something a little bit difficult."

"We knew we would struggle here, but we didn‘t expect the race to be this tough right from the start," said team manager Massimo Meregalli. "We are still analysing what caused Fabio discomfort today. We haven't found the answer yet.

"Whatever caused it, it was a real shame, because after warm pp we were feeling confident that we could have done a completely different race than what ultimately happened today. We will definitely analyse the data carefully before next week's race."

But all things considered, it could have been a lot worse than losing 12-points from his title lead to new nearest rival and Sunday's race winner Bagnaia.

"It is not a disaster," Quartararo said. "From Sachsenring we always increase our lead. Even in Austria. In Silverstone we talk and say it’s possible we lose some points [but didn't].

"We started here with 65 point lead. It’s a long time since I lost points! It is not a disaster but we need to be able to know what happened today.

"But even if I was P9, I gave everything to fight for one point more and I think these kind of races where you never give up are very good for the championship."

Temporary team-mate Cal Crutchlow finished as the next best Yamaha in 16th place.