MotoGP megastar Valentino Rossi has given the new Circuit of Americas in Austin, Texas, the seal of approval after completing the first day of a three-day private test on Tuesday.

Rossi's first impressions of the all-new venue were positive and the charismatic Italian has trumpeted the importance of a third MotoGP race in America.

"It's important for MotoGP to have a third race in America, we have a lot of good riders from the USA so it's right to be here," said the factory Yamaha rider.

"I really like the track, my first impression is that it is beautiful," he added. "There are three hairpins that are very tight; this is better for Formula 1 overtaking, but for us they are a bit slow. In general the track is good. There is some downhill and uphill and first braking zone is very good.

"The uphill at turn one helps to stop the bike, which is beautiful. For me turn two is the best though and after you enter into the chicane which is very similar to Silverstone. The straight is very long, which is maybe good for overtaking."

Rossi was fifth fastest on Tuesday at 3pm local time behind Repsol Honda pair Marc Marquez and Dani Pedrosa, with LCR Honda's Stefan Bradl next and team-mate Lorenzo. Series newcomer Marquez's best lap of 2m 05.620s gave him the top spot from Pedrosa in 2m 06.140s, with Bradl managing 2m 07.307s ahead of Lorenzo (2m 07.388s) and Rossi (2m 07.924s).

Rossi added: "We have to understand which tyre to use, but the asphalt surface doesn't have any rubber on it at the moment so there is not so much grip at the moment.

"It's very important to have this time as the track is so difficult, the are a lot of blind corners where you have to understand where to brake. We will continue to work on the line to understand the track and also to increase the rear grip on the bike as we suffer in acceleration. The first feeling is positive.

"The city is great, the atmosphere is very good so I think it is a very good place for a race."

Austin will host round two of this year's MotoGP championship from April 19-21.

Update: At the close of Tuesday testing Rossi remained fifth fastest, improving his lap time to a 2m 6.507s, but was left 1.3s from Lorenzo (3rd) and 1.9s from Marquez (1st).

"There are some points where Jorge is faster than me. We have to work more and I have to do more kilometres to get 100 percent from this bike," said Rossi. "It looks like we are working in a good way, except that Honda is very fast. Especially here - Pedrosa and Marquez are very impressive."