Valentino Rossi looked on course for a 200th grand prix podium, in his 350th appearance and just one day after announcing he'll remain in MotoGP by joining Petronas Yamaha next season.

Current Petronas rider Fabio Quartararo was the only person ahead of Rossi as he tipped into Turn 1 at a chilly Circuit de Barcelona-Catalunya with nine laps remaining in Sunday's race.

The Frenchman had an advantage of just 0.7s, but disaster struck as Rossi flicked his M1 from right-to-left for Turn 2, his front tyre casually sliding away to send rider and bike into the gravel trap.

"It's a great shame because it was a good weekend. I was fast from Friday and we were able to improve the bike, so I was strong," said Rossi, who had qualified on the front row.

"I was pushing because I wanted to stay close to Fabio but today the temperature was very low and Turn 2 is always dangerous because on the left you have less temperature on the front tyre.

"Maybe I pushed too much in the corner entry and I lost the front.

"Looking at the data, it's a really, really similar to the lap before but with this temperature, I needed to pay more attention on the left.

"It was a great, great shame because we need a podium after a [strong] weekend like this."

While Rossi's first priority was the rostrum, the huge drop in tyre performance during the closing stages - which saw Quartararo lapping two-seconds slower than when Rossi was with him and three-seconds from his best race lap - means victory was also not out of the question.

"At the beginning, we had a good pace but I tried to ride very sweet for the front and rear tyre because I knew, like everybody, that at the end of the race we will suffer. So we stayed at the front, but I didn't push too much to be there," said Rossi, without a MotoGP win since 2017.

"Fabio, Franco and me were the fastest in the first part of the race. And we were very close. Maybe Fabio was a little bit better, but when the tyre went down a lot, also Quartararo lost very much in the last laps.

"We will never know because I crashed, but if I was able to slow down less [than him] because maybe I was a bit better in the last laps, I can also win."

The Monster Yamaha rider had spent the early stages between Petronas team-mates Morbidelli and Quartararo, moving into second place when Morbidelli made a mistake with ten laps to go.

"After Franco did a mistake into Turn 1, I pushed because I don’t want too much disadvantage from Fabio. I want to try to stay close to him also because I knew the bikes that are usually faster at the end of the race, like Suzuki and Ducati, were not far behind.

"For sure I can arrive on the podium today and I don't know what would have happened in the last laps because everybody – especially Quartararo – slowed down a lot."

Quartararo went on to win the race by just 0.9s from Joan Mir, whose Suzuki team-mate Alex Rins completed a podium covered by 1.9s.

Morbidelli was fourth while Rossi's team-mate Maverick Vinales could only salvage ninth after a bad start. Vinales is now 18 points from title leader Quartararo, with Rossi 50 points back in 11th overall.

Luca 'like a machine'

Rossi's despondent body language as he trudged out of the gravel trap underlined what a bitter blow it had been. But the day wasn't all bad, with brother Luca Marini's inch-perfect Moto2 victory helping soothe his disappointment.

"The victory of Luca is very positive and can help me swallow my mistake," Rossi said.

"Today he impressed me a lot with how he rode the bike. He is like a machine. He never made any mistakes. When Lowes caught him, you could see Luca's style close-up and it was perfect.

"So great congratulations to him… and I hope that he doesn't find a place in MotoGP next year and remains in Moto2!" Rossi joked.

Rossi and VR46 are in talks with Avintia Ducati about a place for Marini on the 2021 premier-class grid.