Dorian Boccolacci set the pace on the opening day of the final GP3 test at the Valencia circuit, ahead of ART's Jack Aitken.
Boccolacci has yet to sign for a team in GP3 for the 2017 season, but has been testing with the Trident team.
His quickest time of 1:21.191 was set late in the morning session, with Anthoine Hubert and Renault-affiliated driver Aitken topping the timesheets earlier on.
Temperatures increased for the afternoon session, with Mercedes junior George Russell putting in the best time, but it was six tenths slower than Boccolacci’s earlier effort.
Consequently, the French driver ended the day fastest, ahead of ART's Aitken, Russel and Hubert – the series' dominant team ending with three drivers in the top four.
In a similar position to Boccolacci, Ryan Tveter is testing with Trident but has yet to confirm his 2017 GP3 plans; he was fifth, ahead of Marcos Siebert.
Jenzer’s Alessio Lorandi and Arjun Maini were next up, with Haas-backed youngster Santino Ferrucci the lead DAMS driver in ninth place.
Nirei Fukuzumi completed the top 10, in the fourth and final ART car, ahead of Ferrari protégé Giuliano Alesi, Steijn Schothorst and Leonardo Pulcini.
A number of red flags disrupted running in the afternoon, with Raoul Hyman and Alesi suffering on-track stoppages.
