Yamaha took the fight to MotoGP champion Marc Marquez at Misano on Sunday, leading 23 of 27 laps and only missing out on victory after a final lap showdown.

But the rider going 'bar-to-'bar with Marquez wasn't Maverick Vinales or Valentino Rossi from the official Monster team, or even Franco Morbidelli on the third factory-spec bike at Petronas.

Instead, it was rookie Fabio Quartararo who came within 0.9s of the first MotoGP victory by a satellite M1 rider, being forced to settle for a fourth podium of the season.

The 20-year-old Frenchman is now directly behind Vinales and Rossi in the world championship standings, despite having the lowest spec M1 on the grid, including 500rpm less than the factory bikes.

So how is he doing it?

"The good thing is that during this weekend Yamaha was competitive and it looks like the other manufacturers had some more problems compared to us," said Rossi, after finishing his home race in fourth place, a fraction ahead of countryman Morbidelli.

"But Maverick [third] and Quartararo are faster than me and Franco, who are a little bit more in trouble, especially on the exit of the corner where it looks like we have a bit less grip in acceleration.

"Why? Maybe because we are taller, we don’t know. But we need to find a solution for us to be stronger."

Since Rossi's last rostrum at Austin in April, Quartararo has not only taken four podiums but three pole positions.

"During this season we have been struggling about the rear grip," Rossi added. "Especially compared to Quartararo, also a little bit with Maverick. They accelerate better and they are able to open the throttle with more grip and they exit from the corner better.

"After the summer break, we modified the balance of the bike and it looks like we improved compared to the first half of the season. But it's not enough, because I am better in braking and corner entry is not so bad. But in acceleration we lose. So we need to find the solution to be stronger in that area."

Morbidelli, who tipped team-mate Quartararo as a race favourite after seeing his pace on used tyres in Saturday practice, said the secret to the Frenchman's success was in the fast corners.

"Fabio is able to take the fast corners at a very high speed, and very little effort. I don’t know how," Morbidelli confessed. "But this is his strong point and we will need to try to improve to reach his level."

Marquez came to a similar conclusion after their close victory battle.

"You can follow the other Yamahas, but Fabio's riding in a very good way, very precise all the time but especially in the fast corners," said the reigning five-time world champion.

"Hewas very, very fast in Turn 11 and I knew if I was still behind him at Turn 11 on the last lap I would lose the race. He was very fast in the fast corners. Even with the slipstream I was not able to follow him."

Vinales led the opening two laps of the race before being overtaken by Quartararo and Marquez. He later reeled the leading duo back in, but was 0.7s short at the chequered flag in third.

"The problem was from lap 3 to lap 8 I didn’t have grip. Then I started to ride in a different way and found a little bit more grip by being more gentle on the bike. When I was behind Fabio [and Marquez], they get a little bit more [grip] than me."

To try to improve his performance, Rossi was using the latest Yamaha parts - carbon fibre swingarm and double exhaust - for the first time in a race.

"I like the new stuff. I know it's not a big difference, but we moved in the right direction," Rossi said. "I have a good feeling when I ride the bike [with the carbon fibre swingarm], it's more precise.

"I think that Quartararo and Maverick are faster this weekend because they are riding better, not [because of the new parts]. So I'm happy about the new parts and think I will continue to use them."

The Doctor feels that while Yamaha has made clear progress in terms of acceleration, mechanical grip remains an issue.

"I think that in acceleration we have improved a lot, in fact in the last races we are closer, also at a difficult track like Austria for example," Rossi said. "I think we made a good job with the electronics, but still we need something about the mechancial side for the rear grip."

But having crossed the finish line 11-seconds behind Quartararo, Rossi concedes there is more potential for his side of the garage to find from the present package: "Anyway, during this weekend the bike worked well so we need us, in our team, to improve in acceleration."

Sunday's result means that Rossi, who rode the M1 from his Motor Ranch in Tavullia to Misano ahead of this weekend, has now gone ten races without a podium.

"I want to try to fight for the podium because the podium here at Misano is always special in front of all the crowd," Rossi said.

"But during the weekend we had some point of the track where I was not strong enough and at the end the race it was a little bit what we expect because the top three have better pace. So this happened also during the race.

"So I arrive fourth, it's a shame for the podium but also we take a little bit too much gap from the top three. So we need to work harder and try to be more competitive in the next races."

Rossi is now five points behind Vinales, who is fifth in the world championship, and 17 ahead of Quartararo.