"Sepang is a very special place - it's not a stop-start circuit; it's a flowing, high-speed track which is all about getting the car to flow from one corner to the next. You need lots of rear-end grip, a strong balance and a car that can ride the kerbs well
while also conserving the tyres. And that's never an easy combination to achieve.
"I think we had a good first day today. I've got a good feeling in the car - it's probably the best feeling I've had in the car around this circuit. Every time I get to a track this year, it always feels light years better than the last time, which is very positive. We're still trying to get a better feeling for the tyres, but we've made some positive first steps.
"This evening, I want to sit down with my engineers and make a couple of changes. We don't yet know where the others are, so we need to keep focusing on our performance, but we're optimistic that we've made a small step forward.
"Hopefully the weather will be okay for qualifying tomorrow."Jenson Button
"It took me quite a while to get to grips with the car's set-up today. I wasn't satisfied with it at first - I didn't really get a balance that I was happy with - but, towards the end of the session, it started getting better. And that was encouraging: it was nice to see that we made some improvements right at the end because it was quite a way from what I wanted.
"We're steadily getting there, and it's starting to take shape, which is encouraging. We don't know what the weather's supposed to do tomorrow, but we'll deal with it whatever it is!"
Martin Whitmarsh, Team principal, Vodafone McLaren Mercedes:
"The timesheets in both sessions suggest that we are headed in the right direction, but our focus this evening is to maximise the car's performance, particularly over a long run, where we know tyre performance will be crucial.
"Lewis made excellent progress throughout both sessions, and we've all been encouraged by his view that the MP4-25 is the best McLaren he's ever driven around this circuit. Jenson struggled to find a satisfactory balance, particularly at the start of this afternoon's session, but he and his engineers worked well together to improve this deficit by the end of the afternoon. I'm positive that he'll make further progress overnight ahead of tomorrow's practice session.
"While we're mindful that the unpredictable Malaysian weather may play a role in determining the outcome of tomorrow's grid, we're nonetheless pleased with the foundations we've laid today."