Kimi Raikkonen led a Ferrari one-two in Malaysian Grand Prix practice on Friday with the world champions back up to speed after a difficult start to the season.
Raikkonen, the 2007 world champion who won at Sepang last year, fired in a quickest lap of one minute 35.707 seconds in the afternoon to end Nico Rosberg's four-session run at the top of the timesheets.
Brazilian team mate Felipe Massa was second quickest in 1:35.832.
Neither Ferrari driver scored a point in the Australian season-opener in the Italian team's worst start to a season since 1992.
Rosberg, who was quickest in all three practice sessions at the Australian Grand Prix, and Williams team mate Kazuki Nakajima had finished one-two in the bright and humid morning session.
Raikkonen had to overcome an early setback when his car's cockpit filled with smoke at the end of the first session and he reported further problems with the new KERS kinetic energy system in the afternoon as well.
Red Bull's Sebastian Vettel was third fastest in the afternoon, ahead of Rosberg.
Brawn GP's championship leader Jenson Button had looked quick in the morning on the circuit that brought him his first podium in 2004, but Rosberg and Nakajima pipped the Australian Grand Prix winner.
The Briton was third and seventh fastest respectively with Brazilian team mate Rubens Barrichello, runner-up in Melbourne, fourth and sixth.
McLaren's world champion Lewis Hamilton was seventh quickest in the morning, a day after he was stripped of third place from Australia for "deliberately misleading" stewards at the post-race enquiry.
To compound his problems, the 24-year-old was also fined 1,200 euros for speeding in the pit lane.
Team mate Heikki Kovalainen was ninth in the afternoon.