McLaren's Jenson Button has described the opening day of practice for this Sunday's Malaysian Grand Prix as a 'satisfactory'.

Button finished just outside the top-ten in both the morning and afternoon sessions - his best lap a 1 minute 37.865 seconds, which left him 1.296 seconds off the pace set by Australian GP winner, Kimi Raikkonen.

Speaking after FP2, the 2009 F1 world champion added that while the McLaren MP4-28 feels a bit better than it did in Melbourne last weekend, the speed and performance is still no match for the likes of Lotus, Red Bull and Ferrari - not that the team expected to make a giant leap forward given the opening round to the 2013 F1 World Championship was less than 7 days ago.

"Today we got through a decent amount of satisfactory work, and we duly gathered some more useful info about MP4-28," Button said. "On a dry track it feels better than it did in Melbourne, but even then its pace still isn't there compared with that of the front-running cars.

"We've identified some further improvements that we can make before tomorrow, though, which is encouraging, and it's been a good day in terms of learning.

"Back at the McLaren Technology Centre in Woking the guys are working as hard as they possibly can to find extra performance - and here in Sepang, too, every single member of our race team is doing a truly awesome job. It's a lot easier to work on a car that's winning races than it is to work on a car that's not fully competitive, so fair play to everyone for getting their heads down and battling through."

Sergio Perez meanwhile was 13th in FP1 and 11th in FP2 in the sister car, his top time a 1m 37.838s, which put him 0.027 seconds up on JB.

"Today was a very busy day, during which both Jenson and I tried a number of options in an effort to decide which spec to go with tomorrow and Sunday. Our car has improved since Melbourne - which is quite cheering when you consider that we raced there only four days ago - and it felt better in both dry and wet conditions today," added the Mexican.

"However, having said that, although as I say it felt better on a dry track today than it did in Melbourne, it would still probably qualify and race a bit better on a wet track than on a dry track, relative to our opposition, so we won't be upset if it rains quite a bit over the next couple of days."

"Today we ran through our planned FP1/FP2 programme, successfully applying the upgrades we'd developed for this weekend, and continuing our investigative work with a view to improving our understanding of MP4-28," summarised McLaren team principal, Martin Whitmarsh. "FP1 was dry, but there was quite a bit of rain towards the end of FP2, in which conditions we were reasonably competitive. Overall, then, it's been a satisfactory day, and we've acquired quite a bit more data which we'll now number-crunch in an effort to optimise our car's spec for the rest of the race weekend."