Monster Yamaha's Maverick Vinales managed to open a big gap over the MotoGP pack on day one of testing at Jerez even though he believes both chassis and engine need more work,

Vinales was 0.754s quicker than second-placed man Fabio Quartararo - who got the new motor for the first time yesterday - with a bike he used with a standard swingarm.

“I think we need to improve the chassis but it is just the first prototype of the new chassis so for sure at Malaysia we are going to have more steps on the chassis," said Vinales, speaking at the track.

"We are working a lot on the new engine trying to understand the positives and negative points of the new bike. This test is quite important for us to decide on the engines and take the right approach to further improve the engine on the track, which is our focus here.

"We are trying to understand the best way to work. For tomorrow my plan is the same. I need to make laps with the engine, and I also need to try the tyres, and then we will see."

Vinales ditched the factory carbon swingarm early and says he won't be going back to it as he figured out after a couple of free practices that it wasn't for him.

“I tried two or three times in some FP1s and for me it was already worse than the normal one I have so there is no meaning to try it now,” he said.