(CNN) -- Kimi Raikkonen is not a driver to get unduly excited.
So It is no surprise that Formula One's "Iceman" is playing down the significance of his Lotus leading the timesheets in practice ahead of Sunday's Malaysian Grand Prix.
It continues what has been a promising start to the season for the Finn, who took the checkered flag at last weekend's season opener in Australia.
"Look at this place: it is hot, it is humid and the track is completely different," the 2007 world champion told Formula One's official website as he downplayed his achievements in practice.
"On top of this we could see rain at any point of the race, so how should I know what is happening on Sunday afternoon?
"The only thing that I can say right here, right now is that the car is good, that the team is working fantastically and that I want to keep the lead in the drivers' standings. Let's see where these factors will bring us in the race.
"At the moment I would say that it is trial and error for all of us, and the more you are able to try, the more you have the chance to eliminate any errors. It looked good for us this afternoon, but it is Friday so it doesn't mean much."
Close behind Raikkonen was reigning triple world champion Sebastian Vettel, on a day which saw dry conditions in the morning and rain in the afternoon.
The Red Bull driver recently spoke of his respect for Raikkonen, who denied that his new found pace would affect their off-track relationship.
"Seb is for me an honest guy -- and, yes, we get along very well," explained Raikkonen. "What happens on the track and life outside the cockpit are two completely different pairs of shoes.
"We are both professionals who can separate one from the other. I always wonder what people are expecting us to do? That we are running with a knife through the paddock seeking revenge after a race incident, or what?"
Vettel, who finished third in the first race of the season, admitted improvements are needed for the Red Bull car ahead of qualifying on Saturday.
"This afternoon we couldn't do so much due to the weather, but this morning it looked OK, although the tyres don't last very long!" the 25-year-old German said.
"We need to try a couple of things now overnight to improve and take a step forward."
Double world champion Fernando Alonso was fourth fastest, edged out by his Ferrari teammate Felipe Massa who went third fastest at the Sepang International Circuit.
Spain's Alonso won this race last year and he will be looking for the fourth victory of his career in Malaysia.
"Today, the car worked well in all conditions and that is very good news for us," explained Alonso. "Now we must see how tomorrow goes, when it could rain at any moment and on a track where tyre degradation is much higher than in Melbourne."
Lewis Hamilton was ninth fastest as he continues his integration into the Mercedes team following his switch from McLaren.
"We made some positive steps with the set-up over the two sessions today," explained the 2008 drivers' champion. "I had a good long run in the dry which has given us a lot of information to look at tonight.
"We didn't learn too much in the wet this afternoon however as the conditions were quite mixed when I went out. We focused mainly on longer runs today so I haven't done a quick lap yet on either set of tyres; that will come tomorrow.
"I'm happy with the direction that we're going and let's see what the weekend brings."