Jenson Button says he has yet to decide on his set-up at Monza after trying several options in Friday's practice.
Fresh from his Belgian GP triumph, Button was back on the pace at Monza, finishing second in both Friday's practice sessions.
The Brit clocked a 1:25.422 in the morning and followed that up by going even quicker later in the day with a 1:25.328.
That, though, put him 0.038s down on his team-mate Lewis Hamilton as McLaren begun their Italian Grand Prix weekend with a 1-2.
"Monza is so different from anywhere else we drive," Button enthused. "The straightline speeds are incredibly high - in fact there are four points around the track where we hit 200mph.
"It's been satisfying to get some dry running under our belts today, because we were able to gather a lot of useful information.
"We tried a few different directions with set-up this afternoon - and some were better than others - but we'll decide what works best before FP3 tomorrow and we'll make the necessary tweaks to get the balance right.
"I'm pretty comfortable with the car; you always want more, but we've done a reasonably good job today."
But despite McLaren holding the early advantage, Button reckons they are in for a good fight this weekend.
"Looking at the data, there are quite a few teams out there that look quick too: it's very close and that's going to make it an interesting race."