Valtteri Bottas rounded off his first day of free practice and first official session with Mercedes with third fastest overall, a little over half-a-second behind team mate Lewis Hamilton.
The Finn clocked in 25 laps in FP1 and 34 in FP2, happy with his day of work but aware it is still early days.
"It was great to be back on track after Barcelona and overall it was a good day today," Bottas said.
"We still have work to do with the car balance but we got all of our running completed without any issues.
"From my side I definitely feel like I can make a step forward tomorrow. It'll be a busy evening for us tonight looking through all the data to see where we can improve but it's a reasonable start."
Bottas admitted that tomorrow's running would better reflect his potential.
"In terms of our pace, it is only practice, so tomorrow we'll find out exactly where we are. These tyre compounds are the right choice for this race.
"The softer compounds all felt good. Everyone is pushing to the limit, as we saw a few times out there today. This track is always quite dirty at the start of the weekend, but we'll get used to it."
GALLERY: all the pics from Friday's action
Keep up to date with all the F1 news via Facebook and Twitter
Lewis Hamilton: Australian GP – Albert Park Lewis Hamilton’s very first Grand Prix weekend…
One driver has a hugely famous name, the other is a special Grand Prix winner,…
As the Ferrari factory in Maranello glows in festive crimson, a sense of anticipation hums…
Lando Norris had just done the hardest thing in motorsport – winning the Formula 1…
A veteran of 41 Grands Prix starts, Howden Ganley - seen here above hitting a…
Ferrari’s Charles Leclerc may not have ended the season with a silver trophy in hand,…