Sebastian Vettel believes that Red Bull Racing is heading to the opening round of the 2013 F1 world championship unsure of where it sits in the pecking order.

Vettel racked up another 100 laps on the final day of pre-season testing in Barcelona, but insists that RBR still needs more time to work through the data, particularly regarding the latest Pirelli rubber, before being able to predict how it may kick off the defence of its third world title in Australia next weekend.

With Mercedes, Lotus and McLaren all enjoying spells at the head of the timesheets, Vettel's name did not feature once during the twelve days of testing spread between Barcelona and Jerez, but the German believes that no team can accurately gauge its true performance after a build-up affected by rain and low temperatures.

"I would say that we never had a winter that was less conclusive than this one, [especially as] the tyres last more or less, depending on how much temperature you are able to create," he told the official F1 website, "I think it is impossible for all of us to read the pace of the cars and to make out any favourites.

"I think we all have been limited by what the tyres can do. It was extremely difficult to read some set-up changes and find a direction with the car as the tyres were simply not good enough."

With each team following its own programme through pre-season, Vettel was also quick to point out that the timesheets were unlikely to show the same picture as he expects to find in Melbourne.

"We all saw the lap times [being posted by Mercedes], but it is a bit unclear at this stage what kind of tyres give what step to you - and I think it sure helps to have a bit less in the car!" he smiled, "In my opinion, lap times didn't matter all through the winter tests - we have to look after ourselves. We haven't been able to tick all the boxes we would have liked to and the last two days weren't as good as we had expected, [although] there is a bit of time left until the season starts."

The three-time champion expects RBR to use that time wisely as it gears up for the first two 'flyaways', which take place on back-to-back weekends in Australia and Malaysia, and revealed that he would be heading to the team's simulator at the earliest opportunity.

"It is extremely difficult to pinpoint any exact area we are not satisfied with, because the tyres are not consistent enough," he repeated, "We need to have a good look at the data between now and Melbourne to have a better understanding of what to expect in Australia and the first few races of the season.

"I would have loved to work more on the set-up, but I don't think that this is only me. I think everybody struggled in that area. We cannot be satisfied with the state of affairs right now."