Williams’ Valtteri Bottas went quickest in the final practice for the Belgian GP as tricky weather conditions led to teams leaving most of their running until late in the session.
The Finn set a lap of 1:49.465 in the final dry minutes of a session that had started in damp conditions not wet enough for intermediate tyres but not quite dry enough for slick tyres.
It meant that the bulk of the session saw little running with only backmarkers testing the early conditions. Marussia’s Jules Bianchi topped the timesheet for half the session, ahead of team-mate Max Chilton and Caterham’s Andre Lotterer.
Sauber’s Esteban Gutierrez was the first to move to slick tyres and when the Mexican went four seconds faster than on his run, it was the cue for action up and down the pit lane.
Bottas’s lap came in a frantic final few minutes in which a number of drivers attempted a soft-tyre run. The Williams driver finished 0.268s ahead of Red Bull Racing’s Daniel Ricciardo, while championship leader Nico Rosberg was third, with a lap 0.274s down on Bottas’.
Kimi Raikkonen was fourth for Ferrari ahead of Mercedes’ Lewis Hamilton and the other Ferrari of Fernando Alonso.