Mark Webber insists that Red Bull remains cautious about the competitiveness of its RB7, despite the car showing signs of an advantage over its rivals.
The new Red Bull topped the first two days at Barcelona this week in the hands of Sebastian Vettel, though more impressive was its ability to lap consistently quickly over a stint, while most teams struggled to hold on to tyre performance.
But Webber is adamant that Red Bull still has issues to focus on and believes Ferrari is looking strong.
When asked if he felt cautious about the RB7 being labelled the best car already, he replied: "Very. Very. We've still got work to do.
"We're learning a lot as we go along, it's still early days with the tyres, early days with the car. As usual it would be nice to go racing as soon as possible to get a feel for where you are. But at the moment we're still working hard on ourselves.
"Ferrari are coming out of the gates very strong. Their car is always out there and they're not hanging around, they've been pretty quick. I think if you're beating Ferrari you'll be doing okay. They're going to be up there.
"McLaren certainly can be there as well, though we're not certain what's going on with them - they're obviously early days with their new car."
Webber covered 139 laps today and says all the teams are working towards more race simulation runs as the pre-season draws near its conclusion.
"We saw a few long runs yesterday from Seb [Vettel], Fernando [Alonso] and a few other guys. Clearly people are starting to prepare a bit closer to go grand prix racing.
"We did some good mileage today, obviously the track was very damp and wet this morning. We don't really know how that affected things this afternoon. We'd do things a bit differently if we were to go again tomorrow - which we probably will."
The Australian is confident that once the season is under way, Red Bull will be able to match any of its rivals in the development race.
"We've seen in the past that Red Bull can go toe to toe with anyone on development," he said. "You don't win world championships if you can't develop the car, and we've got some of the best guys in the pitlane.
"It always helps when you start with a car where the base is not too bad. The RB5 and RB6 were pretty successful and we hope the RB7 can be like that as well."