Rossi and Vinales believe they lost a Yamaha one-two at Valencia

Pace in the wet was an obvious weakness of the 2017-specification YZR-M1, but Yamaha made strides in that aspect this year - which enabled Rossi to fight for victory last weekend.

Vinales had slipped back after starting the season finale from pole, but as rain intensified his pace stabilised and he looked to be getting himself back into contention when he crashed out of fourth behind Rossi.

The race was red-flagged due to conditions shortly afterwards, just as Rossi caught up with leaders Alex Rins and Andrea Dovizioso.

"If I didn't fall and the race wasn't stopped, Rossi and I would've secured a double," Vinales suggested.

Both Rossi and Vinales were running the soft front tyre, as opposed to the medium for Rins and Dovizioso, but the race stoppage gave eventual winner Dovizioso opportunity to switch to the other compound.

Rossi, who crashed out of second place after the restart, concurred with his team-mate's assessment that the red flag hurt Yamaha.

"For me was a great shame, the red flag," he said.

"At that moment we were faster on the track and especially we had the right tyres, Rins and Dovi were more in trouble.

"It was negative for us to stop because at the end we could have arrived first and second."

The Italian made it clear he had no issue with the decision to red-flag the event.

"About safety, it was dangerous, there was a bit too much water," he conceded. "For me, the choice is OK."

Vinales, who was thrown off his Yamaha at speed going through the sweeping Turn 13 left-hander, said he had been suffering with a bike issue from the start.

"The fall was the result of an electrical problem we had," he said. "I don't know if a sensor failed, but the bike was delivering power in a very rare way.

"The problem was reflected in the anti-wheelie and traction control. I needed five or six laps to understand how I had to ride - once I understood it, I was much better.

"Everyone was passing me on the straights because the bike did not give me power. I pushed hard to recover and I ended up flying."