Red Bull's Mark Webber has recorded the fastest time in first practice for the Malaysian Grand Prix at Sepang.
The Australian finished 0.068s ahead of Kimi Raikkonen's Lotus Renault, which was wheeled back into the garage due to a problem with the gearbox.
Reigning world champion Sebastian Vettel was third quickest, with Ferrari's Fernando Alonso and Nico Rosberg of Mercedes completing the top five.
Felipe Massa finished in seventh, sandwiched between Force India duo Adrian Sutil and Paul di Resta.
The Brazilian was involved in the biggest moment of drama in the session, when Esteban Gutierrez spun off the track to avoid a collision.
Lewis Hamilton and Romain Grosjean finished ninth and 10th respectively.
Meanwhile, it was another disappointing day for McLaren, with Jenson Button coming in 11th and Sergio Perez struggling in 13th.
