Hamilton and Mercedes throw down gauntlet
Mercedes were on top in practice, with Hamilton leading a one-two for his team in the first practice session, with the Brit also fastest in the second, ahead of Ferrari's Vettel.
Three-times world champion Lewis Hamilton put Mercedes on top of the timesheets in free practice at the season-opening Australian Grand Prix on Friday, leaving his Formula One rivals with plenty to think about ahead of the first race weekend of the F1 2017 season.
Hamilton and Bottas one-two
Hamilton led new team mate Valtteri Bottas in a Mercedes one-two in the first session and raised the pace in the second to be comfortably quicker than Ferrari's second-fastest Sebastian Vettel on a cloudy day at Albert Park.
Hamilton half a second clear
The Briton's fastest lap in the second session of one minute 23.62 seconds was more than half a second clear of four-times world champion Vettel, who edged Bottas into third.
Vettel's 2007 championship-winning team mate Kimi Raikkonen was fourth fastest in the final session, improving on his fifth placing earlier.
Tough day for Palmer
The first session was largely incident-free but a number of drivers suffered problems later, with Renault driver Jolyon Palmer having a particularly tough day.
Blighted by a seal problem in FP1, Palmer's second session ended quickly as he skidded out at turn 16 and slammed into a barrier, scattering debris on the track and raising a red flag until his wrecked car was winched off.
Felipe Massa's Williams car stopped half an hour into the second session.
Red Bull drivers Dan Ricciardo and Max Verstappen dropped down the timesheets to fifth and sixth fastest in the second session.
New F1 cars showing off speed
The overall speed of the new cars was impressive, many over four seconds faster per lap compared to the corresponding sessions at last year's race.
Three-times F1 champion Hamilton would have been pleased to put down an early marker ahead of his new team mate Bottas, who replaced retired champion Nico Rosberg.
McLaren cut top speed deficit
There was some relatively good news for McLaren, who had struggled in pre-season testing leading to rumours of a split with engine supplier Honda. They sliced their top speed deficit over the fastest cars, though were well down on the lap-time standings.
Hamilton takes pole in Australian GP