Today Williams have put their 2018 car on track for the first time with Robert Kubica, run was held as part of a filming day for the team in Spain on Sunday, 24 hours before the start of F1 winter testing.
"The car is running well," technical boss Paddy Lowe told Sky Sports. "We did find some important issues which we can now solve"
"But we haven't done any performance running, it's not about lap times or the feel of the ultimate pace of the car. It's really about finding those little teething problems that would have wasted time on the first proper day of testing."