Lewis Hamilton has stressed that Mercedes must improve their downforce after the second pre-season test finished at the Circuit de Catalunya.
Hamilton set the quickest time on the final day of running but wet weather rendered times meaningless.
"The conditions today meant that we didn't complete as many laps we would have done in the dry but we have gone through the test items that we wanted to achieve this week," he said.
"We have been working on our consistency over long runs and we managed one run this morning on dry tyres; the car felt okay but the conditions were also very cool, so we cannot draw too many conclusions."
"Like I said in Jerez, I can feel that we have a good foundation with this car but there is still a lot to learn and we know that the name of the game is to improve our downforce."
Hamilton also believes that his personal relationship with his new team is helping progress.
"From a personal point of view, my relationship with the team is growing all the time and it's going really well. I'm happy working with the guys, we are working in the right direction together and I'm pushing to extract the most from the team, just like they are with me."
