Mercedes drivers set the two fastest times in Saturday's pre-qualifying practice sessions at the Formula One Malaysian Grand Prix, showing they are the team to beat again for pole position and in Sunday's race.
Nico Rosberg, who won the season-opener in Australia, led the way with a time of 1 minute, 39.008 seconds at the Sepang International Circuit, a quarter of a second ahead of teammate Lewis Hamilton.
Ferrari's Kimi Raikkonen was third fastest, but more than a second behind Rosberg's time, indicating the silver cars remain in a class of their own in the early stages of the season as all the teams adapt to the new V6 turbo hybrid engines.
Four-time defending world champion Sebastian Vettel, using a new front wing, was fourth fastest, and his Red Bull teammate, Daniel Ricciardo was sixth, separated by Force India's Nico Hulkenberg.
McLaren suffered engine problems, with its two drivers setting only one timed lap between them. The early leader in the constructors' championship had major work to do to rectify the problem in the two-hour gap before qualifying.
Ferrari's Fernando Alonso was seventh on the timesheets, ahead of Williams drivers Felipe Massa and Valtteri Bottas. Force India's Sergio Perez rounded out the top ten.
The practice session took place in dry conditions, though rain was forecast for later in the day, which may affect qualifying.