Jenson Button led a McLaren one-two as the British team eclipsed their rivals in opening practice for the season's first Formula One race, the Australian Grand Prix, on Friday.
The 32-year-old Englishman outpaced compatriot Lewis Hamilton by two-tenths of a second in the final moments of a slow-burning session that reached its climax with just minutes remaining at Albert Park.
Seven-time champion Michael Schumacher, 43, was third-quickest for Mercedes ahead of Ferrari's Fernando Alonso, as the top four spots were filled by four of the six series winners on the grid this year.
But defending double champion Sebastian Vettel of Red Bull was down in 11th place after deciding not to contest the scrap for immediate glory in his new Red Bull car, which he has dubbed "Abbey".
His team-mate, local hero Mark Webber, was fifth fastest ahead of German Nico Rosberg for Mercedes and Toro Rosso's Daniel Ricciardo, whose presence makes this the first Australian Grand Prix featuring two Australians.
Venezuela's Pastor Maldonado of Williams placed eighth and returning 2007 champion Kimi Raikkonen was ninth for the Lotus team, formerly Renault, ahead of Kamui Kobayashi of Sauber.
Alonso's Ferrari team-mate Brazilian Felipe Massa span off and finished up down in 18th place ahead of the two luckless Hispania cars, which failed to clock a time.
The session was run in damp conditions after torrential overnight storms, accompanied by lightning and thunder. After three days of hot temperatures, the season's opening practice began at 20 degrees Celsius (68 Fahrenheit).
The opening minutes saw little real action as the teams adjusted to the conditions, and it was not until mid-session that they began running on dry tyres.
By then, unfortunately for the struggling Hispania team, India's Narain Karthikeyan had already earned the unwanted statistic of being the first driver to pull up in 2012. He went off and immediately switched off the engine.
This was a minor catastrophe for the team as Karthikeyan was driving their only complete car, with the team still hurriedly building their other car for Spanish veteran Pedro de la Rosa in the pits.
Massa also delivered a spectacular 'off' as the leading teams began to push harder in the closing stages, the Ferrari driver making a mistake at turn nine.
He drove off across the grass and spun into the gravel where his car was left beached - a setback for Ferrari as they sought to prove they are fast and reliable enough to be in the title fight this year.