Rubens Barrichello remained upbeat about his prospects for the Italian GP despite finishing the second practice session at Monza only 16th fastest.
The Brawn driver, looking to further reduce the gap to teammate Jenson Button in the standings, believes that many of the quicker cars were on a lighter fuel load.
"We started very quickly at the beginning of the session and then we maintained our times while other people improved a lot," Barrichello said. "I hope the meaning is that people started to take some fuel out. We didn't.
"We were checking our car on a heavy fuel load and it feels OK. In Monza it's very hard to feel a great car on a heavy load. That said, it's fine; I'm happy with it. Fridays mean nothing in a way. It's a pure day of testing and it doesn't matter who's in front and who's behind."
Button finished as 19th fastest after 32 laps.