Davidson stars at Indy

Sato clashed with Sauber's Felipe Massa at Turn 1, damaging the left-front corner of his BAR 006. Davidson, meanwhile, kept his nose clean and recorded some very rapid laps.

"Driving for the first time at Indianapolis has been every bit as exciting as I thought it would be," said Davidson. "It's an interesting track and the long straights create good overtaking opportunities; I've never overtaken as many cars in a practice session as I have today. The track was very dusty at the start of both sessions which made set-up changes difficult to determine.

"The asphalt rubbered-in reasonably quickly through the session so we have been able to make steady improvements. Generally I'm very pleased with what I have achieved at yet another circuit debut. I think we are looking good for another strong race here but it's very hot and humid which should make it even more challenging for Jenson and Taku."

Button ended the day fifth fastest and said: "We've had a really productive day. We made some useful improvements to the car and worked on our performance over longer runs. The track was very dusty when we started out and we set the car up to cope with the oversteer we were experiencing earlier in the day.

"The circuit had a lot more grip this afternoon so the balance wasn't ideal for one lap. We've gathered quite a bit of information which we'll be looking at tonight and which should help us tomorrow."