Lowe admits Williams struggled to unlocks potential of new car in Barcelona

Technical chief Paddy Lowe accpets that instability on corner entry is Williams' main limitation after the tests at the Circuit de Catalunya.

After Williams' relatively disappointing winter testing, in which they never troubled the top of the timesheets, Paddy Lowe has blamed "corner entry instability" for their lack of pace.

Williams had an exceptional 2015, finishing third in the Constructors' Championship, but in the last two seasons they have struggled to regularly reach the points, with Lance Stroll claiming their only podium in that time, at the chaotic Azerbaijan GP in 2017.

On the 2018 car, Lowe told the media: "If we can unlock some progress there, (corner entry instability) we will find a lot more lap time than we've got at the moment because some other aspects of the car are working really, really strongly through other phases of the corner."

Cornering was Williams main problem last season, with the Mercedes engine keeping Williams at the sharp end of the speed trap, so if they can improve their cornering stability, the Williams could be an impressive package this season in terms of winning points.

Sergey Sirotkin set Williams' fastest time of the tests, but still over two seconds away from Vettel's time chart topping lap.

Stroll was the slowest of all 21 drivers to complete laps at Barcelona.