Mercedes' Lewis Hamilton comfortably led the field in the first free practice session of the year at Melbourne's Albert Park, the reigning world champion clocking in 0.551s clear of his closest rival, team mate Valtteri Bottas.
Red Bull's Max Verstappen ended the 90-minute session third, some 0.745s off Hamilton's fastest lap, while Kimi Raikkonen led the Ferrari squad in P4 from Sebastian Vettel in fifth and Red Bull's Daniel Ricciardo in P6.
Australian Grand Prix - Free Practice 1
|2||Valtteri Bottas||Mercedes||1:24.577s||+ 0.551s||29|
|3||Max Verstappen||Red Bull||1:24.771s||+ 0.745s||26|
|4||Kimi Räikkönen||Ferrari||1:24.875s||+ 0.849s||23|
|5||Sebastian Vettel||Ferrari||1:24.995s||+ 0.969s||22|
|6||Daniel Ricciardo||Red Bull||1:25.063s||+ 1.037s||25|
|7||Romain Grosjean||Haas||1:25.730s||+ 1.704s||24|
|8||Fernando Alonso||McLaren||1:25.896s||+ 1.870s||16|
|9||Carlos Sainz||Renault||1:25.922s||+ 1.896s||23|
|10||Stoffel Vandoorne||McLaren||1:26.482s||+ 2.456s||15|
|11||Pierre Gasly||Toro Rosso||1:26.494s||+ 2.468s||25|
|12||Sergey Sirotkin||Williams||1:26.536s||+ 2.510s||25|
|13||Nico Hülkenberg||Renault||1:26.583s||+ 2.557s||25|
|14||Esteban Ocon||Force India||1:26.605s||+ 2.579s||30|
|15||Lance Stroll||Williams||1:26.636s||+ 2.610s||30|
|16||Sergio Pérez||Force India||1:26.767s||+ 2.741s||26|
|17||Kevin Magnussen||Haas||1:27.035s||+ 3.009s||13|
|18||Brendon Hartley||Toro Rosso||1:27.745s||+ 3.719s||16|
|19||Marcus Ericsson||Sauber||1:27.964s||+ 3.938s||28|
|20||Charles Leclerc||Sauber||1:28.853s||+ 4.827s||28|
The first practice session of the year started under Melbourne's blue sky, with air temperatures at 25°C and track temps at 38°C.
Ferrari's Sebastian Vettel was the first man to take to the track, followed by Haas' Romain Grosjean and Sauber's Marcus Ericsson, while the last car to emerge was the Mercedes of reigning world champion Lewis Hamilton.
Twenty minutes and a series of installation laps later, drivers got down to business Red Bull's local hero Daniel Ricciardo laying down a marker, but Kimi Raikkonen and Valtteri Bottas quickly posted the fastest times on Pirelli's ultrasoft tyre.
At the 30-minute mark, Hamilton jumped to the top with a 1m25.694s which put him 0.313s clear of Max Verstappen, but the Dutchman eventually claims P1.
Meanwhile, McLaren was nowhere to be seen despite the fact that the opening session was an important one for the Woking-based outfit as its MCL3 is equipped with an upgrade package which needed to be put through its paces.
Both cars remained stranded in their garage, with their crew working frantically on an apparent exhaust issue affecting the orange machines.
Behind Hamilton, rivals appeared to be closing in but the Brit went faster still on the ultrasoft rubber to keep the contenders at bay, including his team mate sitting in P2.
After over an hour of running, Fernando Alonso finally emerged to post the 14th best time, some 2.6s off the pace. The Spaniard pushed on however to slot in P8, while team mate Stoffel Vandoorne pulled himself up to a promising P10.
The tight mid-field battle held its promise, with only a few tenths of a second splitting the competitive group, but Haas confirmed its early dark horse status with Romain Grosjean finishing FP1 best of the rest in P7.