Vinales finished fourth last time out in the rain at Misano, and lies 16 points adrift of joint-championship leaders Marc Marquez and Andrea Dovizioso heading into this weekend.

But the Yamaha rider endured a dismal opening day of practice at Aragon in damp conditions, managing only the 17th-quickest time, 1.774s slower than pacesetter Dani Pedrosa.

Having said after Misano that Yamaha needs to make a step in the wet to keep itself in title contention against Honda and Ducati, Vinales reiterated that the championship will be “gone” unless it can raise its game.

“Really difficult,” said the Spaniard of his day. “Honestly, we are really frustrated.

“In Misano we did a lot of steps forward with the bike on the wet, I was feeling good, especially the front. But here it becomes so difficult on the bike.

“Especially the acceleration, there is no grip and so much spin that it becomes so difficult to make a lap.

“Going into the corners, I have grip, similar to Misano, but the traction area is worse, the worst part.

“You always try to improve in the wet, as it's also an important part of the game. There are some races now like Japan, Australia, Malaysia, can be a wet race.

“If we are [un]competitive like this, the championship is gone so we have to improve.”

Zarco reference

Vinales’ Yamaha teammate Valentino Rossi fared even worse than Vinales, coming 20th, albeit only 22 days on from breaking his right leg in a motocross crash.

Satellite Tech 3 rider Johann Zarco however was third, only four tenths slower than Pedrosa, and even though the Frenchman uses a 2016 bike, Vinales feels he can still provide a useful reference for the works team.

“I didn't ride behind Valentino, but we have Zarco that is in the front so we have good data,” said Vinales. “Now we have to analyse where we lose so much.

“It's important also that Zarco is in front, we can compare really good the bikes and let's see. But it's strange, [because] in Misano I was in front.”

Additional reporting by Oriol Puigdemont