( CNN ) -- Nico Rosberg kept up Mercedes impressive start to the 2014 Formula One season by posting the fastest time of a tight practice day at the Malaysian Grand Prix . The German driver edged out Kimi Raikkonen of Ferrari and Sebastian Vettel of Red Bull with a time of one minute and 39.909 seconds in the afternoon session -- but it was close . Just 0.061 seconds separated the three drivers . Rosberg 's Mercedes team-mate Lewis Hamilton , who clocked the fastest time on the morning timesheet , ended the day fourth closely followed by Ferrari 's Fernando Alonso and Williams ' Felipe Massa . Temperatures reached a mercury-busting 50 degrees at the Sepang Circuit , impacting tire performance in the afternoon session . `` It was crazy conditions out there , '' Rosberg , who took the checkered flag at the season opening Australian Grand Prix earlier this month , told the sport 's official website . `` In the very , very warm temperatures , it 's a huge challenge to get everything right . '' `` The tires are behaving very differently from how they did in Australia -- so that 'll be my focus . Still , I 'm convinced we can make some useful changes to the car overnight . '' Rosberg 's concerns surrounding the sweltering conditions were echoed by his teammate and 2008 world champion Hamilton . `` It was pretty tough with the temperature and humidity and it 's so important to keep hydrated here , '' said the Briton , who was forced to retire from the season 's opening race . `` The car feels good and our focus was on trying to understand the tires and make sure the balance is right for the weekend , '' he added . Red Bull rising ? Another man pleased with how the sessions went was Red Bull 's Sebastian Vettel . The reigning F1 champion and dominant driver pulled out of the Australian Grand Prix after just six laps . He also suffered the indignity of failing to reach the third qualifying stage for the first time since 2012 . `` I think we had a good day , obviously Friday timings are not the most important thing in the world but it 's good to be up there and in range of the top guys , '' said Vettel . `` There are still some things to solve on the software side and the programming , but that 's the way it is . I think we have to learn a lot but all in all , I 'm quite happy . '' Vettel 's Red Bull teammate Danny Ricciardo finished the day seventh fastest , just ahead of Jenson Button of McLaren and Valterri Bottas of Williams . Elsewhere , McLaren rookie Kevin Magnusson failed to capture the speed which saw him finish second at Victoria Park . The Dane ended the day 12th fastest and highlighted the extreme heat as major factor in how his car performed . `` I 've never driven a car in these sorts of temperatures , so I learned a lot today , Magnusson said . `` The track temperatures are so hot here that the tyres are really suffering , but it 's the same for everyone . `` We need to try and get on top of things before tomorrow 's sessions . '' Flight MH370 tribute . Before the race at the Sepang Circuit on Sunday teams , drivers and officials are planning a host of tributes to passengers of missing flight MH370 . The race track neighbors Kuala Lumpur 's main airport where the plane took off on March 8 . Lewis Hamilton showed his support for the gesture yesterday , tweeting a picture of his car bearing the hashtag `` # PrayForMH370 '' along with the message : `` All my prayers and sympathies go to the friends and families of the passengers on MH370 flight . ''
Nico Rosberg fastest in Friday 's practice sessions for Malaysian Grand Prix . Temperatures reached a sweltering 50 degrees at the Sepang Circuit . The German driver was quickest on his first run of the day, with Lewis Hamilton second and Sebastian Vettel third.