Franco Morbidelli fired his way to the head of the timesheets, denying Takaaki Nakagami the top spot with a late flyer at the death.
The Petronas SRT racer led the way early in the session ahead of team-mate Fabio Quartararo, though weekend form-man Nakagami soon burst onto the scene to break up the Malaysian team’s party.
Quartararo had since moved into the top spot with the fastest lap of the weekend, a 1:47.401 that eclipsed Nakagami’s FP2 time by over three-tenths.
The LCR Honda man lapped just 0.009 slower than the Frenchman on his first push effort mid-way through the session, though was able to reverse the time loss to move his way back into the top FP3 position by the same miniscule amount on his very next tour.
Nakagami’s benchmark would remain unchallenged the bulk of the remainder of the 45-minute test as most of the field behind battled to secure an automatic Q2 berth for Saturday afternoon’s qualifying session.
Morbidelli though looked to be on a impressive final lap as he banged in two sectors just a few-thousandths short of Nakagami, before finding time across the second half of the Aragon circuit to snatch away the initiative by just 0.059.
This forced Nakagami to make do second-his third consecutive appearance in the top two so far this weekend-while Quartararo remained third.
Maverick Vinales was fourth quickest on the sole factory Yamaha, while Alex Marquez backed up Honda’s charge with fifth overall.
Iker Lecuona displayed KTM’s clear speed improvement compared to last weekend’s Aragon encounter with sixth on the combined leaderboard, while Tech 3 team-mate follows his team-mate directly into the pole shoot-out with eighth just behind last week’s winner Alex Rins.
Cal Crutchlow secured the ninth fastest time in the second LCR machine, with championship leader Joan Mir just scraping into Q2 in tenth-the pole shootout contenders covered by just 0.382.
Ducati’s struggles at the Spanish venue continued meanwhile, as Jack Miller managed the marque’s highest position in 11th ahead of Aleix Espargaro’s Aprilia, while Andrea Dovizioso could only muster 14th overall after slipping back from sixth early on.
Johann Zarco was the only rider to run into problems during the session, the Avintia pilot losing the rear of his GP19 Ducati while completing an out-lap late on.
The rear of the Desmosedici slid out on the exit of Turn 9, causing Zarco to slide off down the road-though fortunately unharmed on his way to 21st on the timesheets.
