Fiat Yamaha's Valentino Rossi declared the first hour of practice for the Red Bull U.S. Grand Prix a "good start, good first practice."The world championship leader lapped in 1:21.981 mins. with his final tour of the scenic 2.24-mile racetrack in the hills east of Monterey. The time was quicker than he'd gone in the first practice a year earlier when he went on to win an epic battle with Ducati Marlboro's Casey Stoner.Rossi was pleased "especially because I am on the first position, but also because make already a good lap time and we start from the settings of last year, from a good base. And already the bike was good, but we start to modify, try to improve the feeling on the front, try to use the tires that are a bit different than last year and looks better, especially the last run with the harder tires I do a good lap, a good rhythm. But (Jorge) Lorenzo and (Casey) Stoner are, anyway, on the same pace, so difficult. I mean, I expect Stoner, maybe. I think maybe Lorenzo needs more time, because last year was with Michelin, but was very strong from the first practice. I think we are more or less on the same level now. For sure we have to improve tomorrow."The improvement needs to come from the front end he said, especially going down after the Corkscrew. Improving over there. I think I'm not strong enough at this moment. And also we have to work on the electronics on the bike, because this bike is a lot more jump and more hole, so the bike want to always wheelie. We need to improve the setting for tomorrow."The improvements should make it more stable on a track with multiple elevation changes, "because have a lot of, especially jump like going over crests, so the bike want to always wheelie quite aggressive, so is important understand and try to fix with the electronics."These Bridgestones are similar to the ones Rossi used to such good affect last year, but he said the asphalt was more aggressive, "so we have to go something harder, but anyway, depends from the temperature because is not impossible also make the race with the soft tires, so we will see, we will try to improve."