The roller-coaster ride that is Maverick Vinales' 2020 MotoGP results took their latest dip in Catalunya, where the winner of the previous Misano race managed only ninth place.

The Spaniard appears as bewildered as anyone else by the fluctuations, admitting after Sunday's race:

"It remains the same, you arrive from winning, and then you do this disaster of a race, and your head is crazy. At this moment, my head is crazy, I don't understand nothing."

While the other Yamahas of Fabio Quartararo, Valentino Rossi and Franco Morbidelli were exchanging first, second and third during the opening half of the grand prix, Vinales was down in 15th place and struggling to overtake.

"For sure this result is difficult to swallow, because we came from a victory and from a perfect ride, and you see yourself, you cannot go past P15," Vinales said.

"I spent 16 laps behind Aleix and Cal, and I could not pass, impossible.

"When you don't start good with our bike, the only thing you can do is let laps and laps go past. You cannot overtake until the opponents lose grip.

"So this is what I did, I just cruised for 16 laps behind Aleix and Cal."

Once his opponents began to struggle, Vinales picked his way through to ninth place and was one of the fastest riders on track in the closing laps.

"At the end, the rhythm was not bad, when I was alone I was able to ride 1'41 low while the front group was doing 1'41 high," he confirmed. "But you are at the back. So I prefer to be in the front and riding 1'43!"

"Everything is on the first lap," Vinales added. "We understand really well with our bike, if you don't have a good first lap, you are out of the fight. This is what happened today, so we cannot do more.

"Pretty strange for your mind, but when you understand that this is the maximum potential you could do today, you are calm in your mind."

The result means that Vinales, who came into the race just one point from the world championship lead, is now 18 adrift or Catalunya winner Quartararo, in third.

Vinales identified a poor start, bike set-up and overtaking difficulties as having contributed to his nightmare race:

The start

"The problem is the start. If you start in the front, today it will be completely another result. Because the second part of the race I was very strong," Vinales said.

"Like always, in fourth, fifth gear we have no power so I lost a lot of places on the start. Not in the initial part, but in the second part of the start.

"For example, in Misano it's just first, second, third gear, and you are in the corner [Turn 1]. Here it is fifth gear, full gas. I think this is the difference. When we go to third, fourth, fifth, the other bikes have much more potential than us.

"When I saw this morning who was around me on the grid, I said, "whoah... I should have made first row in the qualifying!" We cannot do more. This is like it is."

The Spaniard, who had qualified in fifth place, dropped to 16th by the first corner.

Yet the other M1s – starting from the front row - emerged from the opening turns in first, third and fourth. Why the difference?

"It's just that I started in the middle of everyone. So when you arrive to the braking with much less speed, you cannot try to gain places. This is basically the problem," Vinales said.

Team director Massimo Meregalli agreed: "The first corner is what cost Maverick a good result today. He was forced to brake earlier and other riders overtook him left and right, losing him a lot of positions. Once you fall back, it's very difficult with our bike to overtake, as we know.

"Maverick also never had the same amazing feeling this weekend that he had in Misano. We will have to analyse the data to see how we can fix this for the next round."

Overtaking difficulties – braking, top speed

Down in 15th by the end of the first lap, it would then take Vinales until lap 13 (of 24) to gain any ground.

"Honestly, when I did the start, I forget about everything, I just thought about passing the rider in front and keep pushing and pushing and pushing, because I understand this morning that the second part of the race will be my strong point.

"But I was very frustrated, I tried everywhere – outside, inside. I don't know what more to try during 16 laps. I changed all the maps to see if it was doing something. But with our bike it's very difficult to overtake, so the only thing you can do is to start first, and to push.

"I even let Aleix and Cal go a little bit to cool down the tyres and see, and nothing worked. The only time I passed was in Turn 5, on the outside, braking. A crazy move, in which I risked a lot to crash, but this is what happens. Then, when I was alone, I had good lap times.

"When you get stuck behind someone, you cannot pass them. This is the main problem."

Vinales had an average top speed in the race of 337.0km/h, which compared with 339.1 for Quartararo, 338.5 for Rossi and 335.3 for Morbidelli. The highest average (top 5 race speeds) was 349.4km/h by Ducati's Francesco Bagnaia.

However, Vinales said his situation was worse than it appeared because he was setting his speeds while in a slipstream.

"The problem is that the bike is very slow. I don't know why. But today I was the slowest one with Morbidelli. And I was with the slipstream," Vinales said. "For me it's quite curious. The bike was in the slipstream, and the bike was even slower than the ones that were in front without the slipstream."

Gearing might have been a factor.

"Yes, I was all on the limiter in sixth gear for the last 100 metres, so maybe this affects it a little bit. But anyway, it's always the same. Exiting the corner, I have to say I had good grip, because I caught the other riders a lot. But when I changed to third, fourth, fifth and I have big problems."

While all the Yamahas are struggling in terms of engine performance, Vinales' overtaking issues were exacerbated by being weak in the braking zone.

"All weekend I was struggling on braking, with the grip," he said. "For example, if I am in the front, I can brake very late, and I make myself able to stop the bike and turn. But when I'm behind them, it's impossible. Every time I brake late, I arrive really on the tail and I have to pick the bike up and go straight.

"I tried during all weekend to be with other riders, and I already knew it, I could not pass. So it's something we have to work on."

Set-up changes

In order to try and improve the braking issues, Vinales and his crew had moved away from the race-winning set-up discovered at the second Misano event.

With hindsight it was probably a mistake.

"We did the same work [as usual this weekend], it's just we never found a good feeling," Vinales said. "I started with the bike from Misano, which I was feeling really good with. Then trying to find something more, we changed the bike and we lost the way.

"We had a lot of problems with the front, it was locking a lot during all the weekend, so we just tried something very different to try to avoid that front locking. We avoided the front locking, but we lost in other places," he explained.

"We tried many, many things on the bike, maybe too much, and for sure we lost the way this weekend. We arrived to the warm up with a very different setup, and we didn't know what to choose.

"So this is something we need to pay attention to, because the bike from Misano worked well, especially in that race."

Dovizioso: It's down to the rear tyre

It wasn't mentioned by Vinales, but fellow championship contender Andrea Dovizioso believes that the new rear tyre construction is the root cause of the topsy-turvy results for many of the frontrunners.

"How do you explain the average points of riders this season and, for example, what's happened with Maverick? 1st, 10th... It's never happened that much in the past for a lot of riders," said the Ducati rider.

"This year the championship is crazy because if we had the same tyres as last year, I think, the results would be similar to last year. Everything that is happening is related to the new [tyre] casing."