Mercedes showcased their speed during opening practice at the Australian Grand Prix on Friday.
As was so common throughout last year, Nico Rosberg and Lewis Hamilton topped the timesheets.
Rosberg edged his world champion team-mate by just 0.029 seconds as a time of 1:29.557 set early in the 90-minute session proved the best.
Valtteri Bottas was third fastest in his Williams but some 1.191 seconds slower than Rosberg.
Toro Rosso duo Carlos Sainz and Max Verstappen were the busiest drivers as both completed 30 laps and ended up fourth and sixth quickest respectively.
Sebastian Vettel and Kimi Raikkonen were fifth and eighth respectively in their Ferraris, while Bottas' team-mate Felipe Massa ended up seventh.
Pastor Maldonado was ninth, while his Lotus team-mate Romain Grosjean completed just five laps.
Red Bull's Daniel Ricciardo was 10th fastest in front of his home fans.
McLaren's troubles continued as Jenson Button and Kevin Magnussen - who is replacing the injured Fernando Alonso in Australia - got through just 13 laps between them.
Manor Marussia pair Will Stevens and Roberto Merhi did not complete a lap, and neither did Sauber's Marcus Ericsson and Felipe Nasr.
Sauber's court battle with Giedo van der Garde is ongoing.
Fittingly after their dominance in 2014, Mercedes registered the first two lap times of 2015 – Rosberg setting a 1:31.319 before improving that to 1:29.557.
The 17-year-old Verstappen led the drivers out in his Toro Rosso, and his first time was respectable albeit well behind the contenders.
Reigning world champion Lewis Hamilton trailed his team-mate Rosberg before closing the gap to just 0.029 of a second halfway through the session.
What followed with half-an-hour to go was the season's first spin, Ricciardo losing control – albeit momentarily – at turn 15.
The Australian complained about the Red Bull's driveability on the team radio soon after.