Lewis Hamilton ensured that Australian Grand Prix winners McLaren remained on top of the F1 pile as round two of the 2012 season got underway just days after leaving Melbourne.
The Briton, who left Australia frustrated at his failure to convert pole position into victory - which went to team-mate Jenson Button - waited until midway through the 90-minute opening practice session at Sepang before stamping his mark on proceedings. Although his initial benchmark was almost immediately eclipsed by Red Bull's Sebastian Vettel, Hamilton bounced back on his next flying lap, setting a 1min 38.021secs target that would remain through to the end of the session.
With the teams opting to get some high fuel running in ahead of forecast showers later in the day, the order remained largely unchanged in Hamilton's immediate wake, with Vettel holding on to second, just over half a second down on the McLaren, and Nico Rosberg taking third for Mercedes, a further couple of tenths adrift.
Rosberg's team-mate, Michael Schumacher had briefly held top spot, and was the first man into the 1min 38s, but had to settle for fourth spot, just over a hundredth of a second shy of the faster W03.
Romain Grosjean completed the top five for Lotus, but missed some early running after his initial outing was cut short by what appeared to be a hub failure on the right rear corner of his E20. Back on track, however, the Frenchman was the last driver to get within a second of Hamilton, shading Red bull's Mark Webber and Lotus team-mate Kimi Raikkonen.
Times through the middle of the field proved to be well matched, with a second covering Schumacher through to 14th-fastest Kamui Kobayashi, and included Melbourne winner Button, who was forced to miss the end of the session after the McLaren mechanics discovered an oil leak on his MP4-27. Unlike Hamilton, therefore, the points leader was unable to conduct much race simulation running, and could miss out again if the expected rain arrives in time for FP2.
Paul di Resta finished FP1 in ninth place, having had to catch a major sideways moment midway through the 90 minutes, while Force India team-mate Nico Hulkenberg sandwiched Button in ninth and tenth. Williams reserve Valtteri Bottas was next up, marginally getting the better of Albert Park stand-out Pastor Maldonado on his first Friday morning appearance of 2012, while Felipe Massa managed only 13th fastest time his new Ferrari chassis. That, however, was better than team-mate Fernando Alonso, who was a couple of places further back as the Scuderia focused on its aero woes.
Neither Toro Rosso or Sauber showed as well as may have been expected, with Jean-Eric Vergne the best of the quartet in 16th as the two STR entries sandwiched the best of the Caterhams. The second green-and-gold machine was 19th in the hands of Vitaly Petrov, ahead of the remaining Sauber, which Sergio Perez described as 'undriveable' midway through the session.
At the back of the field, Marussia continued to put the miles on its MR01, with Charles Pic having to play catch-up after a delayed start. That, however, was better than Narain Karthikeyan managed, the hapless Indian again grinding to a halt out on track as his HRT's hydraulics went AWOL for the third free session in a row. Karthikeyan was still faster than team-mate Pedro de la Rosa, despite covering less than half the laps of the Spanish veteran. Both drivers lapped in the 1min 45s but, with the team hoping its DRS system would be fully functional in Malaysia, should be closer to the 107 per cent mark needed to ensure its first race appearance of 2012.