MELBOURNE, Australia (AP) -- Mercedes driver Nico Rosberg set the fastest time in Saturday's pre-qualifying practice session for the season-opening Formula One Australian Grand Prix, well clear of his rivals.
Rosberg was 1.4 seconds quicker than the next fastest driver, Jenson Button of McLaren, around the Albert Park street circuit.
Ferrari's Fernando Alonso was third fastest, narrowly ahead of Rosberg's teammate Lewis Hamilton, while four-time world champion Sebastian Vettel of Red Bull was down in 12th place, 2.8 seconds off the pace and complaining on his radio about his car.
"The car is horrible," Vettel radioed to his garage. An engineer replied: "Can you explain what is horrible?" Vettel responded: "Drivability, the car doesn't accelerate."
His teammate Daniel Ricciardo fared better, setting the fifth fastest time, less than a hundredth of a second ahead of Force India's Nico Hulkenberg.
Despite dark clouds around Melbourne, rain held off for the practice session but was forecast to arrive later Saturday and may affect qualifying.
Ferrari's Kimi Raikkonen was seventh on the timesheets, ahead of McLaren rookie Kevin Magnussen, Force India's Sergio Perez and Williams driver Felipe Massa.
The Caterham cars finally got out on track for a full session after doing next-to-no running on Friday, but Lotus continued to have reliability problems. Romain Grosjean did not complete a lap, while Pastor Maldonado got through the session but his car coasted to a halt on track soon after it finished.