Repsol Honda's Andrea Dovizioso - runner-up at the last two rounds - was sixth, while team-mate and former title contender Dani Pedrosa, returning to MotoGP action exactly two weeks after fracturing his collarbone at Motegi, lapped a cautious ten seconds off the pace before calling it a day before the halfway mark.
Valentino Rossi, who won his second race of the season - and first since breaking his leg at round four - last Sunday at Sepang began one of his favourite events with seventh place.
Colin Edwards (Tech 3) , Randy de Puniet (Honda LCR) and Loris Capirossi (Rizla Suzuki) completed the top ten.
Mika Kallio, riding in what looks like being his last MotoGP event before being replaced by Carlos Checa for the last two rounds, recorded the eleventh best time for Pramac Ducati.
Poor weather is also forecast for Saturday, but may improve for Sunday. MotoGP has not had a wet race so far in 2010.
Australia is the last of three flyaway events, in three weeks.
9. de Puniet