Valtteri Bottas says that he is "blown away" by the pace Mercedes showed during Saturday's qualifying session.
The Silver Arrows locked out the front row at Albert Park for the first time since 2016, with Lewis Hamilton beating Bottas to the top spot.
Bottas held provisional pole after the first run but lost out to Hamilton, who improved on his last run. Bottas' fastest time was just over a tenth slower than Hamilton's.
However, Ferrari's Sebastian Vettel, who ended the session in third place, was seven-tenths of a second down on Hamilton. While Bottas admits shock at Mercedes' pace, he stated that it is still all to play for in Sunday's race.
"I’m a bit blown away by the performance we have today,” said Bottas. “Obviously yesterday was looking good but it’s always practice.
"It’s just the first session this year that really counts in terms of lap time and I don’t think anyone in the team could have imagined we’d be in this position after the testing we had.
“But everyone’s been working so hard. that made this possible. But it’s only one session, tomorrow is the main day.”
Hamilton added that the team made some strong steps forward following winter testing as it worked on altering its set up rather than developing new parts.
“Coming from Barcelona we’ve made some really big steps forward in the last couple of days with set-up and we brought that here and it seems to have worked.
"But there was also a little bit of work done after the two weeks where we analysed everything and made some small corrections. I really was not expecting to see the performance difference that we have here. It had been so close throughout the whole weekend between us.”
Speaking about his own run in qualifying, Hamilton added: "The second lap was definitely a lot better than the first which is not always the case. It's always quite difficult on the second lap to pull that amount of time out.
“But the first lap I made a mistake, which is unusual for me. But it was OK I just brushed it off and kept moving. We just kept working away, chipping away at our pace, our balance throughout the weekend.”