Melbourne: Mercedes started the new Formula One season as they left off on Friday as Nico Rosberg and Lewis Hamilton timed quickest in opening free practice for the Australian Grand Prix.
Rosberg, last year`s race winner, clocked the fastest time of one minute 29.557 seconds, ahead of defending world champion Hamilton in 1:29.586.
Rosberg and Hamilton are expected to make a flying start to the year after the constructors champions improved both their chassis and engine in pre-season testing.
Four-time world champion Sebastian Vettel, driving for Ferrari for the first time since his switch from Red Bull, was fifth with a best lap of 1:31.029.
Finland`s Valtteri Bottas in a Williams and Spaniard Carlos Sainz in a Toro Rosso were third and fourth fastest in the session, while Australia`s Red Bull driver Daniel Ricciardo was 10th in 1:31.570.
Dutch teenager Max Verstappen, set to become the youngest ever Formula One driver at 17 years and 166 days in Sunday`s race, was sixth fastest, some 1.5secs behind Rosberg.
McLaren had a mechanical issue with a power-unit component and their drivers Jenson Button and Kevin Magnussen were well down the charts -- echoing their problems in testing.
Meanwhile Sauber sat out the session as a legal fight over their driving line-up dragged on in the Melbourne courts.
The team lost an appeal against a court ruling ordering them to let Giedo van der Garde race for them this week, leaving them with three drivers for their two cars.
A contempt of court action aimed at ensuring Sauber complies with the ruling was adjourned until the afternoon at Victoria Supreme Court.
Observers said van der Garde had a seat fitting in Ericsson`s car, but apparently did not have the super licence he needs to take part.
The new Manor team, born from the ashes of Marussia after it went into administration, also skipped practice as they went through basic checks, having missed pre-season testing.
"Today is effectively our first day of testing, so we`re currently working through our checklist and tackling any issues as they arise," the Manor team said via Twitter.
Reports said that in anticipation of an auction of the team`s assets, which eventually didn`t happen, all of their hard drives were wiped, leaving them to rebuild their software systems.