Alexander Sims set the pace on the first day of GP3's midseason test at Valencia on Thursday.
While the 30-car field will return to the Formula 1 support bill on the streets of the Spanish city next weekend, the two-day test is taking place on the Circuit Ricardo Tormo permanent facility.
Sims set his best time in the morning session, where the majority of the quicker laps were posted. Ryo Haryanto was quickest in the afternoon session, just ahead of Sims this time, but the Indonesian's time was only good enough for 20th overall.
Manor's Adrian Quaife-Hobbs was second, while Michael Christensen and Nico Muller prevented fifth-placed Lewis Williamson from making it a top-three sweep for the Brits. Championship leader Nigel Melker was sixth quickest, just ahead of the day's early pacesetter Gabby Chaves.
ART Grand Prix didn't feature toward the top of the overall times as it opted not to run in the morning to conserve its tires, which are much more fragile this year than they were in 2010. However, Valtteri Bottas was third fastest in the afternoon session.