Though describing his recent form as shocking, Lewis Hamilton remains convinced he can make his mark in the two remaining races.

While he began the second half of the season with a win (Hungary), he has pretty much struggled ever since, and while Mercedes claims that a cracked chassis will have significantly contributed to his problems in the last two races, the 2008 world champion is in no doubt where much of the blame really lies.

"I would say it since the break has been shocking," he told the Independent, referring to his form. "Maybe it is down to the direction taken with the car. Maybe the set-up hasn't been right. I don't really know.

"I am just as focused," he continued, "but sometimes you feel you have not been in the right place at the right time. In Suzuka we should have had a good race. I was really quick. The wing level I had there was really different to Nico so we should have been really good that weekend, but I was unlucky to get a puncture. In the last race (Abu Dhabi) qualifying didn't help and from then on it spiralled down.

"I am hoping this weekend to put myself in a better position," he added. "I feel positive for this weekend."

A winner here last year, the inaugural event at the Circuit of the Americas, Hamilton, who has been given a new chassis for the final two races, is feeling much more confident.

"On the long runs it did feel better," he smiled, "so I'm hoping when the car is heavy with fuel, I would like to think it will be as good as it is now. Fingers crossed it will be better this weekend, but I've no idea if that was the reason behind my recent struggles.

"It's difficult to pinpoint what it was," he admitted. "Sure the crack didn't help... it wasn't a crack, it was a hole. But it doesn't matter, it's in the past. I'm looking forward. We have two races to go, and all of us in the team are focused on ending the season on a high and taking that foundation with us into the winter."