Ferrari appeared to have the faster cars in winter testing but it was Hamilton who had the quickest lap of 1 minute, 22.600 seconds in the first two official practice sessions at the Formula 1 season-opening race at the Albert Park circuit.
Hamilton's teammate Valtteri Bottas was second quickest in FP2, 0.048 seconds slower than the Brit.
With pressure surging to beat the juggernaut that is Lewis Hamilton to the Driver's title, Sebastian Vettel and his Ferrari team are in full knowledge that a third consecutive Melbourne victory, is key in taking such fight to the five-time World Champion.
But in the second session, when teams started to stretch their legs a little, the best Ferrari could do was fifth with Vettel, almost nine-tenths of a second behind Hamilton.
"I really have a positive buzz from driving the auto today and it's not too dissimilar to how it was a year ago." said the reigning champion. "The vehicle feels like it's in a similar place to where it was in Barcelona, which is positive coming to a different track", said Hamilton.
"We've got a contract that says that we're the first race and that runs until 2023".
Briton Hamilton, the victor of four of the last five titles, believes the Silver Arrows have a battle on their hands this season against Ferrari, whose vehicle showed impressive pace and reliability during winter testing.
I can feel I have the vehicle under me that I had in testing, but it doesn't do the same thing.
"We didn't bring a lot of new parts to the auto, but we were able to optimise the package that we have".
But the Finn added: "We haven't seen the full performance from any of the other teams".
Vettel slid onto the grass at turn one early in the afternoon run. Feels quite odd. Seems to be something wrong.
Vettel later bolted on softs and put in a lap of 1m23.473s to go fifth fastest, subsequently describing the auto as "still a bit wobbly" over the radio.
Formula 2 Champion, George Russell in the Williams, but also Lando Norris for McLaren, the latter becoming Britain's youngest ever driver in Formula 1 at 19 years old.
"It has been alright. If we can get that confidence and that groove back, there's a lot of lap time in that round here".
British-born Thai debutant Alexander Albon had a tough day, crashing his Toro Rosso to lose his front wing and causing a brief halt in the first session before spinning off track several times in the second.