Valentino Rossi is expecting a 'difficult' race as he and the Yamaha team venture back to the United States for the first ever MotoGP round to be held at Indianapolis.

After winning his third race in a row last time out at Misano, Rossi needs to score just one point more than Stoner this weekend to put him in with a shout of wrapping up the title at the next round in Japan.

For the moment though, Rossi is concentrating on the weekend in hand around a circuit he believes is likely to be tough on tyres, while the slightly cooler weather conditions could also play a factor in the weekend's results.

"I am still on a high from Misano, which was an amazing day, but now we are facing a different challenge," he states.

"It's very exciting to be going to Indianapolis, such a famous and historical place for motorsport, but it's obvious from reports that it's going to be quite a difficult race for everyone. Of course we have no data but we're also expecting the surface to be quite tricky for the tyres.

In addition, Rossi has raised some concerns about the prospect of racing against some of the most fearsome walls in motorsport, although he is confident that the high-speed circuit, which has played host to many legendary races, will meet safety standards.

"I hope the track is safe, we know the walls are quite close in some places but hopefully it won't be a problem. We will find out on Friday! It's fun to be going to a new place in America and I hope there will be a lot of fans, even if it's not quite as many as at the Indy 500!"

Davide Brivio, meanwhile, is not underestimating the challenge facing the Yamaha team this weekend, but with momentum on their side, he is confident Rossi can move one significant step closer to wrapping up the title.

"Everyone in our team really enjoys racing in America so we're excited about going back there, and even more so about going to such a fantastic, historical place as Indianapolis. It will be great fun exploring the track and the area, and we're anticipating a great weekend.

"Of course we know it's going to be hard, as it always is when we go somewhere new, but the momentum is with us after three great races and we will be aiming to continue in the same way. Our team is very motivated and we will be looking to get as good start on Friday morning and then to make the most of each session from then on."