Mercedes completed a strong Friday at the Australian Grand Prix, leading the way during an eventful second practice in Melbourne.
For the second straight session, Nico Rosberg outpaced team-mate Lewis Hamilton at the Albert Park circuit.
Rosberg's 1:27.697 on soft tyres was quickest, with Hamilton just 0.100 seconds slower.
Ferrari had shown their potential earlier in the session and Sebastian Vettel and Kimi Raikkonen ended up third and fourth respectively.
However, Vettel was 0.715 seconds slower than Rosberg – highlighting the advantage Mercedes have during the opening weekend.
McLaren's struggles from opening practice continued, but Jenson Button did complete 21 laps – while Kevin Magnussen got through four before finding a wall and bringing out a red flag.
Sauber's weekend finally started despite their ongoing legal battle, with Felipe Nasr and Marcus Ericsson both getting out on the circuit.
For the second straight session, Manor Marussia failed to complete a lap.
An engine change meant Daniel Ricciardo sat out the session, while Felipe Massa's water leak on the power unit of his Williams meant he also watched on.
Williams' Valtteri Bottas, Red Bull's Daniil Kvyat, Toro Rosso's Carlos Sainz, Lotus duo Pastor Maldonado and Romain Grosjean and Force India's Nico Hulkenberg rounded out the top 10 for the session.
Ferrari dominated the early parts of the 90-minute session as Raikkonen and Vettel traded places at the top before the latter set at 1:29.801.
Grosjean and Maldonado both went off in the first 15 minutes before Magnussen's red flag.
The Dane – replacing Fernando Alonso in Australia – ran off, through the gravel and into the wall at turn six.
Raikkonen and Vettel both broke 1:29, the former Red Bull driver setting a 1:28.412.
Ferrari's marker was, predictably, bettered by some way by Mercedes halfway through the session as the reigning constructors' champions ran soft tyres.
Rosberg – who had earlier complained of his DRS not working – went quickest with a 1:27.697 before Hamilton moved second, just 0.100 seconds slower.
Longer runs followed for teams and it meant Rosberg's time went unbeaten.