Quartararo led home the Yamaha charge as he dropped one place from his grid slot of 14th, having failed to escape the first part of qualifying earlier in the day.
Team-mate Franco Morbidelli was a place further back in 16th, while wildcard Cal Crutchlow capped off a miserable day for the Iwata firm in 18th following a long-lap penalty.
Quartararo said that trying to push beyond the limits of the Yamaha M1’s capabilities contributed to a mistake that prevented him improving his best lap at the end of Q1.
“Unfortunately we were super-slow,” summarised Quartararo. “This is our potential now. We have no turning, no power, no downforce, nothing.
“If you want to try and get into Q2, you have to try to brake over the limit, and then you make a lot of mistakes.
“In the second time attack I just tried to brake much later and I made a mistake. But it’s the only way to make a good lap time.”
Yamaha's slump in form comes off the back of an encouraging weekend in India, where Quartararo scored only his second podium of the season and Morbidelli had his second-best finish of the year in seventh.
Asked what plans there are to make progress up the grid, Quartararo replied: “There is no plan. The bike is the same as three years ago; we change things but we never make a step forward.
“We tried everything possible on the bike and there is no way we can really find a big step. It’s missing so much that we cannot focus on only one thing.”
Yamaha test rider Crutchlow raced with the new aerodynamic fairing used by Quartararo at the Misano test, and said his performance in the race confirmed his belief that it is not the right development direction for the marque to pursue.
“It was their plan all along to use this aero, I didn’t want to use it, but in a way it was good we used it, because now we know that this bike is not working in the direction they are pushing,” the British rider said.
“I used it in two tests, I didn’t like it, and now we confirmed the problem. So now we need to use something else.”
Explaining the problems with the aero package in more detail, Crutchlow added: “The bike is difficult to manoeuvre and you can’t stop the bike with so much downforce.
“You lock the front of the bike and you lose a lot of rear grip, and then the bike becomes really difficult to ride and accelerate from the corner.
“I can homologate something else [for the Sunday race], but I don’t know what we have in the stock cupboard. But this is why we are here, to understand what is good and what is bad.”
