LEWIS Hamilton faces a tough choice ahead of Italian Grand Prix qualifying on Saturday.

The 2008 Formula 1 world champion was third and fourth fastest respectively in Friday’s two free practice sessions around the historic Monza circuit.

However, judging the Herts-born McLaren star’s race pace is hard as he tried two different downforce packages, one without the now infamous F-duct aerodynamic aid – and achieved similar times with both.

“We had two good practice sessions today,” said the 25-year-old world championship leader.

“This morning, in P1, we ran with the higher-downforce package, and the car felt good, but it wasn’t as fast along the straights as we’ve experienced in the past.

“During P2, I was using a different downforce package to Jenson [Button] – running with a lower-downforce rear wing and without the F-duct.

“So we need to go through all the data tonight [Friday] to decide which approach works best. Both configurations were quick, so we’re not in a bad position.”

The classic Monza track was always expected to suit Hamilton’s car, with its long straights.

Lewis added: “The two different packages felt fairly similar – one is slower down the straights but quicker through the corners, and the other is quicker down the straights but slower through the corners – and they pretty much balance themselves out over the course of a lap.

“As I say, we haven’t yet decided what to run tomorrow; it’s about determining which is better on high fuel, and whether there’s more potential in one over the other. We’ll decide this evening.”

Reigning F1 world champion Button was quickest in this morning’s first practice session, faster than Hamilton, but was only fifth fastest in the afternoon.

Button said: “Lewis and I were trying out different levels of downforce today – gathering data to see what works best around here. I stayed with the F-duct and higher-downforce package, and was reasonably happy.

“We have a lot of data to go through, so it will be a busy night tonight. But we’re pretty competitive with both packages, which is positive because it means the car is working efficiently.

“Our car is mechanically strong, so we just need to confirm what downforce level to run.”

McLaren Mercedes team principal Martin Whitmarsh added: “Coming to a high-speed circuit like Monza without the benefit of pre-race testing really sharpens your game.

“Today, we spent the day running two significantly different bodywork iterations, trying both high- and low-downforce configurations in an effort to understand their effects – not only on a flying lap but across the course of an entire race.

“It’s pleasing to report that both packages appear competitive. Our aim now is to comprehensively analyse the data we generated today in order to find the optimum path for each driver over the course of the rest of the weekend.

“Given the amount of data, and the parity of each package, that’s no easy task – but, as always, I’m entirely confident that our engineering team will make the right decisions, and that we’ll be in the hunt for the remainder of the weekend.”

Final practice takes place on Saturday at 9am with 2010 Italian Grand Prix qualifying at 1pm.