Ducati's Danilo Petrucci didn’t hold back as he described the condition of the COTA asphalt after opening MotoGP practice in Austin, Texas.

Further work has been carried out to try and reduce the notorious bumps, but after setting the 13th fastest lap time Petrucci said:

"The track is worse. No grip. The strange thing was that the lap time was improving lap by lap, because at the beginning, the track was like a road, with bumps, holes, and everything. And I think this doesn't reach the standard for a MotoGP track.

"I mean, it's unbelievable why we are riding here. The track and the circuit in general is unbelievable in a positive sense, but the asphalt is unbelievable in a negative sense. It's a shame, because it could be very very much faster, but you have to ride trying to deal with the bumps.

"Anyway, we have to work, and we'll see. We have the data from Dovi and from Jack, who are a little bit faster than me, so I cannot say that I am happy, but I'm quite conscious of my potential."

However, countryman Valentino Rossi felt "the condition of the track was not so bad, better than last year."

Miller and Dovizioso were third and fourth fastest in FP1, behind Marc Marquez (Honda) and Maverick Vinales (Yamaha), with Rossi in fifth.

Marquez, who was 0.2s quicker than when leading the same opening session last year, said: "I am quite happy with how we started the weekend. Of course, we still need to understand many things. We need to try to understand the best lines on the track as it is really bumpy, which way we are setting up the bike and which way to ride.

"It is always like this, every year is different. We are working on it as tomorrow it looks like the weather will be unstable so it is important today in FP2 to try to do a great job and try to be consistent from the beginning."