Fast Friday for Vinales, Rossi

Maverick Vinales got the better of COTA favourite Marc Marquez during a phantom qualifying session at the end of Friday practice in Austin, which also saw Monster Yamaha team-mate Valentino Rossi complete the top three.

Vinales began the day in second place, just 0.078s behind Honda's six-time winner Marquez, then turned the tables by 0.044s when riders put new soft rubber at the end of FP2.

"I think today it was very important to work on the basic set-up, because in Argentina we misunderstood some things. I think we worked quite well here today. I tried to be very competitive, especially on the first laps, but we still have to improve," said Vinales, who couldn't replicate his front-row qualifying during the Termas de Rio Hondo race.

"We have to be more precise in the first laps and I need a little bit more grip, especially on the rear, because I still didn't feel that I'm at my best. It's important to be at the top today, because I think tomorrow it's going to rain, and we need to start at the front.

"The track is very bumpy. It was funny, when I was pushing I made a big lateral slide, but honestly I was lucky I didn't make a big highside.

"But anyway normally in the bumpy tracks I'm there. Like Silverstone where it's bumpy I didn't suffer so much. I'm not afraid for sure!

"The good thing of the track is that there are fast and slow sections. So if you go fast here it looks like you can go fast everywhere. I like this track a lot. Without the bumps it would be incredible. But like this it's okay for me, I can still ride. Turn 18 for me is the most dangerous. It's very easy to make a highside there with all the bumps.

"Now I would like to improve the slow corners, especially the exit. Still we didn't set-up with the electronic so I'm quite happy because we are competitive but still we need to improve.

"For me, I always feel good in fast corners. I can carry a lot of speed and that's very good. But also I think we are braking better than in Argentina. I do a lot of lap time under braking, so also it's important to have good brakes to improve in the race and overtake.

"So for sure one of my main focus for tomorrow is the braking area and electronic on the exit of slow corners."

The late time attacks were given extra importance due to the threat of rain on Saturday morning, which would mean the ten riders that are heading straight for Qualifying 2 have already been decided.

"For sure, I'm expecting to be fast in qualifying [whatever the weather]," Vinales said.  "In Valencia I finished at the top in the wet. It's true that I also crashed, but I was one of the fastest on the track. I have a good feeling, and when you have a good feeling it doesn‘t matter what the conditions are like."

But Vinales admits it'll be a tough task to end Marquez's unbeaten COTA run on Sunday.

"It's going to be so difficult to beat him here. He is very fast here but for sure it's never easy so I'm going to push at my best to bring the bike at the maximum. If we can take out the best of the bike I think we can be there."

Having struggled in the early stages of the previous races, after a fast qualifying, Vinales practiced overtaking other riders on Friday.

"Yeah here I ride with people and seems to be a little bit easier to overtake. I'm using very tight lines. [This is a wide track] so I can prepare the overtake better than Qatar. Qatar is just one line. Here you can use different lines. It's easier."

Rossi was also pleased to have a provisional place in Qualifying 2, but warned he has 'some problems' with his race pace.

"Today wasn't so bad, especially the third position is very good. I did a good lap, and this is very important in order to stay in the top-10. We have some problems with the pace, I'm not fantastic on the race tyre. We have to work on the balance of the bike, but for a first day it's quite positive," said the Italian, a distant second to Marquez in Argentina.

"The weather forecast for tomorrow is grim, but we're hoping it's wrong. Maybe the weather will be good tomorrow, but if it rains we will all start from zero again. We'll need to try to understand the conditions and we need to find a good setting for the wet, but anyway we hope to have a dry race on Sunday."