Vettel is turning out for his fifth consecutive year with Ferrari as the season’s curtain-raiser edges ever closer.
The team appeared to have the quickest car in pre-season testing, stoking hopes that the German will claim his first title for the iconic Italian team.
Vettel has finished first the last two years in Melbourne, but was dented by the second practice, in which he never seemed to hit top gear.
Despite showing the best form in testing, Vettel was 0.8secs slower than the Mercedes on both short, qualifying-style runs and longer race-style runs.
There is suspicion that the team are withholding their true speed for once the chequered flag waves on Sunday morning, but Vettel was upfront about the preparation.
And he identified “car feel and handling” as two specific problems ahead of the race at Melbourne’s Albert Park circuit.
“It probably was a tricky day for everyone,” the 31-year-old said.
“But I think for us we are not yet where we would like to be.
“Not in terms of lap time, but more in terms of car feel and handling.
“I think we didn’t really get into the groove and into the rhythm and that’s quite important around here.
“I’m hoping that tomorrow is a better day. If we can get that confidence and that groove back, there’s a lot of lap time in that round here.”
Mercedes looked the pick of the bunch as Lewis Hamilton headed a Silver Arrows one-two in the second practice.
Hamilton has not won in Melbourne since 2015 and played down the importance of winning the season-opener, saying: “It’s a long season, so I don’t particularly feel it’s the most important thing.
“I think it’s really about finishing races and analysing and making sure you are getting as many points as you can, of course.
“But I’m not really one for needing to stamp authority.”