Lewis Hamilton bagged early bragging rights over rival Sebastian Vettel after clocking the fastest time in opening practice for the Australian Grand Prix.
Ferrari may have had the edge after pre-season testing in Barcelona, but it was the Mercedes driver who set the pace with a lap of one minute 23.599 seconds on soft tyres.
In response to the reigning champion, Charles Leclerc gave an indication of what the Ferrari was capable of, recording a lap of one minute 23.673 seconds, before Vettel went four-hundredths of a second quicker for second place with one minute 23.637 seconds.
Red Bull's Max Verstappen recorded a time of one minute 23.792 seconds, good enough for fourth place and was followed by Hamilton's team-mate Valtteri Bottas on one minute 23.866 seconds.
The midfield was a packed affair – with 0.682 seconds separating Kimi Raikkonen in sixth and Sergio Perez in 16th.
Daniil Kvyat in his Toro Rosso was 0.1 seconds quicker than Red Bull's Pierre Gasly, with Haas driver Kevin Magnussen and Nico Hulkenberg rounding out the top 10.
There was late drama in the session, with rookie Toro Rosso driver Alex Albon losing his front wing after a spin at turn two, leading to a red flag, while Bottas braked on the grass and nearly put his Mercedes in the wall at the penultimate corner.
Renault struggled during the session under blue skies in Melbourne, an electrical problem consigning Hulkenberg to the pits for the majority of the session and Daniel Ricciardo struggling to find pace on his home track with a deficit of two seconds behind Hamilton.
However, there is only so much that can be gauged from the 90-minute first practice session with drivers operating varying fuel levels and trying different set-ups.
Albon is one of three rookies who will be making their F1 debut in Australia, with Britons Lando Norris and George Russell occupying two of the bottom three spots in the session.
Norris was clearly keen to get his eye in at Albert Park, completing 31 laps with a fastest time of one minute 25.966 seconds for 18th place, while Russell was five seconds off the pace in 20th with a time of one minute 28.740 seconds.
