Nico Rosberg insists his car still isn't '100 per cent' despite topping both free practice sessions on the first day of the Australian Grand Prix as Mercedes dominated proceedings.

Picking up from where it left off in 2014, Mercedes went a long way to confirming assertions that it has maintained a significant advantage over the competition by dominating both practice sessions, more than a second clear in FP1 and seven tenths up in FP2.

Things were much closer between its protagonists though, with Rosberg emerging ahead of his 2014 title-winning team-mate Lewis Hamilton by just a tenth.

Related Articles

Indeed, despite the margin over his other rivals, Rosberg admits problems finding the right set-up - a complaint of his pre-season - remains a concern in the context of his anticipated tussle with Hamilton.

"It's been generally a good start and I'm happy with today," he said. "Of course, with Lewis it's always nip and tuck, so it's always quite close and I need to nail it tomorrow and after tomorrow. For now I haven't found the car balance 100 per cent; the long run was okay but the short run had much too much oversteer for now.

"There's a bit too much of that so I need to work on that this evening, but it's such a mission because there are so many set-up options we can use to get the car right that it's almost infinite. To know which one is the right one so that you are not just masking the issue with another parameter is really complicated."

Despite this, Rosberg is pleased to see Mercedes has maintained its advantage over the competition over the winter.

"We always have an eye on the other teams, but definitely it has been a good day for us and a good start so we are very confident for tomorrow. But of course with Lewis it is super close and it's always going to be a battle. We just need to nail it to be in front tomorrow and after tomorrow."