BMW Sauber's technical director Willy Rampf says the team's new car has matched its expectations following its maiden test at the Valencia circuit.
The Ferrari-powered C29 showed promising form in the first test in Spain, where it was the second fastest car behind the Ferraris.
Rampf said the team was pleased with the trouble-free test, and claimed the car was performing as expected.
"All in all we can be satisfied with the reliability of the car," said Rampf. "We completed 1,000 kilometres over the three days without encountering any major problems. Of course, we have to make some adjustments and modifications, but that's what tests are there for."
He admitted, however, that it was very hard to judge how competitive the car is.
"That is even more difficult to assess this year than in previous years. All we can say is that our car is delivering the performance expected based on our simulations and measurements in the wind tunnel.
"Vastly differing fuel loads make it impossible to draw an absolute comparison with other teams' cars."
Rampf also said Pedro de la Rosa and Kamui Kobayashi were already working very well together despite both being new to the team.
"Both drivers are new to the team and so we're all still getting to know each other. However, the working relationship between the drivers and team has got off to a very good start.
"With Pedro you can see that his vast well of experience has given him a broad base of technical knowledge, which is extremely valuable for all involved.
"Kamui gets his impressions across very quickly, which means he can give the engineers the information they need to work out the changes required. All in all, the drivers and engineers are already working together very productively."