Kimi Raikkonen ended the final in-season test at Silverstone on top, setting a lap of 1 minute 30.665 seconds.
The Fin, whose fastest lap was six tenths up on Fernando Alonso's best effort from yesterday, clocked 103 laps of the Northamptonshire venue as teams mate the most of the dry conditions after the heavy rain yesterday.
Mercedes junior Esteban Ocon was once again second fastest, just over half a second behind Raikkonen, with Red Bull's Pierre Gasly in third, the problems that blighted him yesterday now resolved.
Force India's 17-year-old development driver Nikita Mazepin was fourth, two tenths of a second quicker than McLaren's Stoffel Vandoorne.
Valtteri Bottas of Williams was sixth fastest, he spent the afternoon running an extended rear wing to simulate 2017 downforce levels.
Hass junior Santino Ferrucci was seventh, ahead of Jolyon Palmer (Renault) and fellow rookies Sergio Sette Camara (Toro Rosso) and Jorndan King (Manor).
Pascal Wehrlein was also in action, driving a 2014 Mercedes to conduct 2017 tyre compound tests for Pirelli.