The team worked through its planned programmes on a busy Friday in Barcelona, with a particular focus being on learning about the three tyre compounds.
"It has been a productive day with both cars running reliably and completing their respective programmes," explained Trackside Engineering Director, Andrew Shovlin.
"Conditions haven't been especially easy, the wind has been strong and unpredictable which caught out both our drivers on their SuperSoft laps but we weren't the only ones who seemed to be struggling to get all the sectors together.
"It was difficult to know quite what to expect with the tyres here as the conditions in the winter were so cold, and it is the first time we have run the thinner tread Pirelli tyres.
"For this reason, we spent more time than usual trying to understand how all three compounds compared to make sure we carry good information into the race.
"Our car worked very well here in the winter, but we've seen in the early races that both Red Bull and Ferrari have added a lot of performance and that was also evident today in their performance today.
"We do need to find a bit of pace, especially on the SuperSoft tyre given that qualifying is so important here, but the car wasn't perfect today so hopefully we can make a bit of progress overnight and give Red Bull and Ferrari a tough time tomorrow."