Stoner not worried by 2006 Ducati form

Last year the factory bikes were off the pace all weekend in California and could only manage eighth and tenth in the race, but Stoner started the 2007 US Grand Prix by comfortably topping both Friday practice sessions.

He said the performance was further evidence of the progress Ducati had made since last season, as the team have so far shown much better form at all the circuits where they had been weak in the past.

"There were a few tracks where Bridgestone and Ducati struggled at last year including Donington, but we managed to be fastest on race tyres there this year," he said.

"There doesn't really seems to be any weak points for the Ducati this year. In Mugello we were struggling with the set-up a little bit but we sorted that out in Barcelona and minimised them as much as we could and it's working everywhere."

Stoner has lost the last two races after rivals on Michelins maintained their pace better over a Grand Prix distance, but the Australian was confident that his tyres would hold up at Laguna.

"We tried a different rear this afternoon and we've already done over race distance on the front," he said.

Although Stoner's teammate Loris Capirossi was only ninth fastest, a second slower, he was optimistic about his chances of improving as the weekend progressed - especially after finding that the set-up that took him to a season-best second place at the Sachsenring was also effective at Laguna.

"This afternoon we tried two very different set-ups, one like we used at the Sachsenring, the other like we used before Germany," Capirossi said.

"The Sachsenring set-up works better here, so we are focusing on that and working at improving my feeling. If we can keep going in this direction tomorrow, I am confident I can have a good race on Sunday."