While Lewis hit the ground running around Yas Marina, Trackside Engineering Director Andrew Shovlin says there is still work to do to be ready for qualifying, and what should be another tight battle with Ferrari and Red Bull.
"A busy day for the drivers and everyone in the garage," said Andrew. "We had a large development programme focused on 2018, this required both cars to devote the entire P1 session towards this work but despite the ambitious programme, we managed to get through it all successfully.
"The track cools significantly into the evening session and our focus shifted towards qualifying and race preparation. The car seems to be working reasonably well although we've got plenty of areas we can look to improve overnight.
"Valtteri in particular was not comfortable with how the car was handling on a single lap so we have a bit of work to do there. Lewis found the car more predictable on low fuel but there are still some areas that we can find a bit of time.
"The long run balance was quite consistent but it's difficult to know where everyone is as there seemed to be a lot of traffic out there today and many cars were struggling to string clear laps together.
"We are expecting another tough battle for pole tomorrow, having seen strong times posted by both Red Bull and Ferrari through the sessions, but we are determined to finish the season on a high and will make sure we give it our best shot."