Lewis Hamilton got his Malaysian Grand Prix weekend off to a good start by topping the first free practice session at Sepang.
The McLaren driver ended up more than half a second clear of the rest of the field, with reigning world champion Sebastian Vettel the man who got closest for Red Bull in second place.
Nico Rosberg was third fastest for Mercedes, 0.792 seconds behind Hamilton and just 0.013s ahead of teammate Michael Schumacher.
Romain Grosjean looked set to carry his pace across from Australia as he went fifth fastest for Lotus, ahead of the second Red Bull of Mark Webber and his teammate Kimi Raikkonen. Paul di Resta was eighth, with last week's race winner Jenson Button separating him and Force India teammate Nico Hulkenberg who completed the top ten.
Valtteri Bottas made his practice debut with Williams, finishing up 0.06s ahead of teammate Pastor Maldonado in 11th. Felipe Massa was the best of the Ferraris in 13th, two places ahead of Fernando Alonso.
Sergio Perez finished up down in 20th place, having gone off twice in his Sauber and describing his car as undriveable. Narain Karthikeyan meanwhile came to a halt in his HRT due to a gearbox problem.