Admittedly, the 298.3km/h set with a prototype version of the 2023 Yamaha engine, behind only a 300.0km/h by Ducati’s Jorge Martin, had been in the slipstream of team-mate Franco Morbidelli.

But it was still a major step compared to his 20th place on the speed charts with the current much-maligned engine during the San Marino grand prix weekend.

Quartararo’s average speed with the new engine on Wednesday morning, a more accurate figure since it uses the top five speeds for each rider, was also promising at 296.3km/h compared with a best of 298.6km/h by Martin.

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“This morning we worked pretty well on the electronics of the new bike because the character of the engine is slightly different,” said Quartararo. “The top speed looks really good, so I feel super happy! It‘s a great feeling.

“I got a great slipstream to set the 298km/h top speed this morning. But the average of the speed was also good, compared to the others, this is super important.

“We still need to work on the first part of acceleration and improve more. But we are only in September. We still have the Valencia test, then Sepang and Portimao.”

Having lost points to Ducati’s Francesco Bagnaia at the last four races, Quartararo then completed a morale-boosting day by also topping the afternoon session - when he tried some new fairings and winglets - with the fastest lap of the test.

“The difficult thing will be to be back in Aragon on the 2022 bike!” Quartararo said.

Mixed opinions on new Yamaha chassis

While the new engine and aerodynamics can’t be used until next season, Quartararo also had a new chassis that will at least be on standby for next weekend in Aragon.

“Fabio is really considering to use it,” confirmed team director Massimo Meregalli.

“This chassis has something good and bad, like always. Fabio thinks it’s more good than bad and Franco [Morbidelli] the opposite. He was not feeling as good as Fabio.

“But it will be important to evaluate it in Aragon, because it’s not enough to evaluate a new chassis or an engine at a single track.”

Morbidelli set the 12th fastest lap of the test, 0.560s behind Quartararo.

“Unfortunately, the hot lap didn't come out well. But anyway, our pace and our average level were really good. We found many different solutions. They are all interesting, so we need to make the right choices,” Morbidelli said.

“The team and Yamaha did a wonderful job in stepping up in terms of items for the bike. They did a great job at home, and these two days of testing were really good to appreciate the job they did.”

Aragon was one of Yamaha's toughest events last season with Quartararo the only M1 in the points with eighth place, while Bagnaia won his first MotoGP race.