Red Bull's David Coulthard fears he may have to revise his goals for the Formula One season starting next month after mixed results with the new car in pre-season testing.
"At the moment we're not going to achieve the goals I had for the year," the Scot told the official Formula One website "But we've got some more time to develop and hopefully, once we've done that, we can try and achieve them."
The 35-year-old, winner of 13 Grands Prix with Williams and McLaren, said fifth place in the championship was still a realistic target for his Renault-powered team.
"Of course it's realistic. Other teams are not doing anything that's not humanly possible, it's just that they've got the right mix of technical investment and facilities. That's what we need to continue to develop at Red Bull and then the results will come.
"The current things we are working on are the gearbox, overall reliability and basically building our relationship with Renault and learning about its electronic systems," said Coulthard.
"The package is not yet optimised so we've got a lot of work to do to get the performance we want."
The new RB3 car is the first designed for the team by former Williams and McLaren designer Adrian Newey. Coulthard's Australian teammate Mark Webber has struggled to fit comfortably into it.
The season starts in Australia on March 18.