Fortec Motorsport's Sten Pentus repeated his morning performance to head the final afternoon of Formula Renault 3.5 collective testing at Motorland Aragon
The Estonian driver's time of 1m42.650s shaded P1 Motorsport's Walter Grubmuller by 0.188 seconds.
Echoing his morning position of third, SG Formula's Jean-Eric Vergne claimed in-house Red Bull honours by finishing one place ahead of Red Bull Junior colleague Brendon Hartley in the rival Tech 1 Racing camp.
In a day given over to the testing of a low-downforce aerodynamic configuration that will be in use during this season's sprint races, Pentus set his fastest afternoon time with just two minutes of the three and half hour session remaining. The second year man put his strong form in part down to prior experience of the low-downforce set-up from yesterday, and also due to his collaboration with driver coach, and former Formula 3 driver, Laurent Delahaye.
"We worked on a race distance yesterday," said Pentus, "concentrating on testing different set-ups and not running any new tyres. Because we did a race simulation, we also tried the low-downforce, so I think I may have been one step ahead of some people today.
"This morning, I just needed to do one installation lap and a short run on new tyres to do the fastest lap. The car was perfect, but I still have a lot of work to do myself. The faster I go the more things I discover that I need to improve in my driving, so this performance doesn't really increase expectations ahead of the first race."
Filip Salaquarda took fifth in the sole ISR car to take to the track. The Czech driver's father, and team boss, Igor Salaquarda is hopeful of securing a second driver in the coming weeks.
"We have a lot of drivers interested, but most are pushing for cheap deals which we is something we won't do," said Igor Salaquarda. "I'd be perfectly happy to run one car, but it looks like there could be an opportunity to sign someone next week."
Junior Lotus Racing showed well, with the experienced Daniil Move and team-mate Nelson Panciatici in sixth and eighth, sandwiching KMP Racing's British F3 graduate Victor Garcia.
Former Macau winner Keisuke Kunimoto was ninth for Epsilon Euskadi, ahead of Jan Charouz. P1 Motorsport will have the opportunity to undertake private testing with drivers Charouz and Walter Grubmuller at Estoril next week, after an earlier private test was snowed off.
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