Lewis Hamilton enjoyed the perfect start to his F1 2019 season by topping both of the Australian GP's opening practice sessions, with Mercedes opening up a significant advantage over their rivals.
Though Hamilton only marginally edged out the Ferraris in first practice, the world champion led a dominant Mercedes one-two in Practice Two.
Valtteri Bottas finished 0.048s behind Hamilton's 1:22.600 in the sister W10, but Red Bull's Max Verstappen was the closest non-Mercedes, eight tenths of a second off the pace in third and just ahead of team-mate Pierre Gasly.
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Ferrari, meanwhile, many paddock experts' favourites for the title, were abnormally quiet in the second session.
Sebastian Vettel was the lead Ferrari car in fifth, while Charles Leclerc was ninth and over a second slower than Hamilton.
The Monegasque rookie, who enjoyed a strong P1, also span out in the closing minutes of Friday's running.
Ferrari's Charles Leclerc span late on during practice 2 ahead of the Australian GP.
Merc ahead, but are rivals sandbagging?
The gap between Mercedes and Ferrari was particularly surprising considering the Scuderia's impressive winter testing, and Hamilton's assertions about their speed prior to the season-opener in Melbourne.
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But it all changed later on Friday.
So, were Ferrari and Red Bull holding back?
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"Looking at Renault at just one tenth behind Red Bull and ahead of Leclerc, that all smells to me of Red Bull and Ferrari sandbagging," said Sky F1's Karun Chandhok. "I think they are waiting for tomorrow.
"I expect to see a proper battle for pole position. But we don't know where Red Bull-Honda are."
Sky F1's Martin Brundle added: "We have to stay calm.
"What it does tell us is that Mercedes have honed in on their car. But the Ferrari and Red Bull look great on track.
"So any headlines other than 'Mercedes are right in the hunt' will be misleading."
There will be no hiding place on Saturday, when qualifying takes place at 6am on Sky Sports F1.
Alfa Romeo impress, Williams struggle
The battle to lead the midfield appears to be just as intense. And it was Alfa Romeo - led by veteran Kimi Raikkonen on his return to the team - who pulled clear of their rivals in P2.
Raikkonen shone in sixth and finished within a second of Hamilton at the top of the timesheets, and within a tenth of his former Ferrari team-mate Vettel.
Renault suffered their fair share of reliability issues on Friday but enjoyed a much more promising end to the day, with Nico Hulkenberg seventh and just ahead of team-mate and new recruit Daniel Ricciardo.
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The rest of the pecking order was hard to call: Haas, Toro Rosso, Racing Point and McLaren filled positions 10-14.
But there appears to be a clear backmarker at the start of F1 2019: Williams.
The Grove team, hampered by a delayed start to pre-season testing and whose technical director Paddy Lowe took leave before the first race of the season, were worryingly off the pace on Friday.
George Russell and Robert Kubica propped up the timesheets in both sessions, and were four seconds off the leading pace in P2, and almost two seconds slower than their closest midfield rival.
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