World champion Lewis Hamilton produced an impressive early benchmark as he led a Mercedes 1-2 in the first practice session ahead of the Australian GP.
The British driver posted a 1m24.026s on his second set of Ultrasoft tyres, over half a second clear of teammate Valtteri Bottas and three-quarters of a second faster than Max Verstappen in third for Red Bull.
Though an ominous sign, the saving grace for Mercedes' rivals is Verstappen, Kimi Raikkonen and Sebastian Vettel all set their times on the Supersoft compound which is around half a second slower in terms of performance.
The battle between Red Bull and Ferrari does look fierce based on Practice 1 though, with less than three-tenths covering the four cars and the Scuderia taking a more measured approach to the largely unrepresentative session.
Despite hopes that the midfield could close the gap to the frontrunners this year, seven-tenths was the margin between Daniel Ricciardo, who had a tricky session in sixth, and Romain Grosjean in seventh for Haas.
The Frenchman's position does consolidate the pace his American team showed in testing though, but McLaren are lurking with Fernando Alonso eighth and Stoffel Vandoorne tenth.
Strong improvement should be expected though as their running was limited with both cars after the double world champion was hit by a repeat of the exhaust problems as seen in pre-season testing.
Renault also hinted at their expected progress with Carlos Sainz moving into the top 10 in ninth, six-tenths faster than teammate Nico Hulkenberg in 13th.
Like Haas, Toro Rosso was another surprise performer from pre-season and the junior Red Bull team also looks in reasonable shape with Pierre Gasly 11th in an impressive effort from the young Frenchman.
The usual midfield leaders of recent years, Williams and Force India hinted at their ongoing struggles after failing to get a car into the top 10 but both remain closely matched with less than three-tenths covering their four drivers.
Rookie Sergey Sirotkin was the highest placed finishing P12 with Esteban Ocon and Sergio Perez sandwiching Lance Stroll in 14th and 16th respectively.
Both are traditionally known to take it easy in practice, with Force India also evaluating an upgrade package they have brought, so it will be interesting to see if they move up as the weekend progresses.
Despite higher expectations, Sauber continues to bring up the grid with Marcus Ericsson almost nine-tenths clear of new teammate Charles Leclerc as the Monegasque took it steady in his first session around Albert Park.
With dusty conditions and different agendas, times from the first practice are usually irrelevant, a first look at the order may emerge when teams complete qualifying and race simulations later in Practice 2.
