Lewis Hamilton has admitted that he is concerned about tyre wear at this weekend's Malaysian Grand Prix.
The Mercedes driver was fastest in the first practice session, while teammate Nico Rosberg was quickest in the afternoon in Sepang.
The 2008 world champion told Sky Sports News: "It's too hot for the tyres. The tyres aren't really working well in these conditions and even though we've got the hard tyre and the medium here, the tyres do not feel great. But it's the same for everyone."
Hamilton started the opening race of the season in Australia from pole position, but was forced to retire from the race after just three laps.