Felipe Massa says Williams now need to up the pace after the FW36 came through Friday's practices without any issues.
The former Ferrari driver, who joined Williams in the off-season, was billed as one of the early season favourites having set the pace in the final pre-season test.
However, Massa was unable to carry that pace through to Melbourne where he finished Friday's running in 12th place.
He posted a 1:31.119, which put him 1.494s off the P1 pace and two-tenths behind his team-mate Valtteri Bottas.
It was nevertheless a solid start to the weekend for Williams, whose FW36 had a trouble-free day.
"It was good to get a strong number of laps on the track today and a chance to understand how the car is behaving at this particular circuit," he said.
"The car didn't show any problems which is very positive as reliability will be important this weekend.
"There is a lot for us to work on tonight to improve the set-up of the car, but on the whole this has been a positive day for us and we head in to the weekend happy with how things have gone so far."