Sergio Perez has admitted that Force India may need a couple of Grands Prix before they are up to speed with their competitors.
The team only ran the 2015 car at the final pre-season test in Barcelona after its development was delayed over the winter.
While Perez was happy to clock up 130 laps at the Circuit de Catalunya on Sunday, the Mexican has revealed that the constructor remains behind schedule.
He told reporters: "It's a promising start. I think it will take us a couple of races to get where we want to be. There's a lot of work ahead of us and we are a couple of steps behind the opposition.
"I'm going into Melbourne with just one day in the car. It is not ideal, but it is what it is. We have to try and take the best out of that situation.
"We are not expecting big things for the first couple of races, but our direction is clear and we know what we have to work on to improve our car."
Force India finished sixth in the 2014 Constructors' Championship.