Four days of pre-race testing did little to shake up the order as opening practice for the Malaysian Grand Prix got under way at Sepang, with Ferrari and McLaren again showing that they will be the teams to beat this weekend.

Determined to bounce back from his Melbourne disappointment, Felipe Massa posted the fastest time of the opening 90-minute session, setting the initial pace at 1min 34.972secs, already under the general pace from last week's test. Massa had McLaren's Fernando Alonso for company as the Spaniard got to within three-tenths of a second of the Ferrari but, with only Lewis Hamilton and Kimi Raikkonen also getting within a second of the pace, the weekend is already taking on an ominous shape.

Last year's Sepang surprise, Nico Rosberg, proved to be best of the rest on this occasion, the young German finding his best lap right at the end of the session to vault into fifth spot. With BMW and Renault further down the order, Mark Webber claimed sixth for Red Bull, ahead of the two Toyotas - Jarno Trulli and Ralf Schumacher sandwiching Williams reserve Kazuki Nakajima in eighth - and Robert Kubica, who rounded out the top ten.

The Pole was joined on track for the session by test driver Sebastian Vettel -much to Nick Heidfeld's apparent chagrin - and the German put the second BMW Sauber entry in twelfth spot, one behind David Coulthard who, despite completing a session-low seven laps, managed to muster enough pace for eleventh.

There was some encouragement for Scuderia Toro Rosso less than 24 hours after its STR2s were protested by rival Spyker, as Tonio Liuzzi took 13th fastest time, comfortably ahead of 16th-placed Adrian Sutil who again proved to be the quicker of the two Spyker drivers. The German proved to be in the same second bracket as both Renault drivers, despite the fact that Spyker opted not to run at the Sepang test in order to concentrate on finishing its new aero package.

Surprisingly, perhaps, almost the entire 22-car field completed a decent number of laps - with only Coulthard, Scott Speed and Anthony Davidson failing to reach double figures. The American and Briton clocked nine apiece, with Davidson no doubt keen to give his injured back as much cosseting as possible before the serious business of the weekend begins. Super Aguri team-mate Takuma Sato was 17th fastest, ahead of both 'works' Honda drivers, as Rubens Barrichello and Jenson Button again struggled for pace and languished at the very bottom of the 'top' 20.