The purpose of the test was to give the 10 teams experience of Pirelli’s 2019 compounds and make comparisons to the 2018 versions.
Leclerc went faster than Vettel’s benchmark after just a few hours and improved early in the afternoon to end up on a 1m36.450s.
That was 1.7s slower than the pole time for Sunday’s Abu Dhabi GP, a 1m34.794s set by Lewis Hamilton.
Pierre Gasly, driving for Red Bull ahead of his own 2019 move, remained Leclerc’s closest challenger.
The Frenchman was 1.5s adrift after spending most of the day on a 1m37.976s, before improving twice in the final hour – first by four-hundredths of a second and then by another two-hundredths to end on a 1m37.916s.
Lance Stroll ended his first full day in a Racing Point Force India third fastest as he awaits confirmation of a race drive with the team for 2019.
The Canadian’s 1m38.044s, set at the very start of the afternoon, remained his best effort for the day.
Mercedes’ Valtteri Bottas finished fourth fastest, like Stroll with a lap time set in the first half of Wednesday’s nine-hour session.
Carlos Sainz jumped up the order with a 1m38.547s, set in the final hour, to end his McLaren debut fifth fastest for the day.
He edged Renault’s Artem Markelov by half a tenth, while 2019 Williams driver George Russell emulated Sainz’s rise by leaping to seventh on a 1m38.802s after taking over from Robert Kubica for the final few hours.
Toro Rosso returnee Daniil Kvyat and Haas’s F1 test debutant Louis Deletraz split the new Williams teammates.
Antonio Giovinazzi completed the 11 runners. The Sauber driver caused a red flag when he stopped in the tunnel exiting the pitlane in the afternoon.
|1||Charles Leclerc||Ferrari SF71H||1’36.450||135|
|2||Pierre Gasly||Red Bull RB14||1’37.916||129|
|3||Lance Stroll||Force India VJM11||1’38.044||122|
|4||Valtteri Bottas||Mercedes F1 W09 EQ Power+||1’38.448||143|
|5||Carlos Sainz||McLaren MCL33||1’38.547||150|
|6||Artem Markelov||Renault R.S.18||1’38.590||129|
|7||George Russell||Mercedes F1 W09 EQ Power+||1’38.802||55|
|8||Daniil Kvyat||Toro Rosso STR13||1’38.862||155|
|9||Louis Deletraz||Haas VF-18||1’39.069||117|
|9||Antonio Giovinazzi||Sauber C37||1’40.435||129|
|10||Robert Kubica||Williams FW41||1’44.208||39|