Low temperatures and high winds punctuated a tricky day of practice for the MotoGP Aragon Grand Prix, which was headlined by a crash for championship leader Fabio Quartararo.

Monster Energy Yamaha MotoGP rider Maverick Viñales topped both sessions to lead a Yamaha one-two-three, with the Spaniard ending the day 0.249s ahead of Quartararo and Franco Morbidelli.

The first 45-minute session of the weekend was delayed by over half an hour due to the cold weather, with Michelin’s tyres requiring a track temperature minimum of 12 degrees to operate safely.

Quartararo, who leads Suzuki’s Joan Mir by 10 points, wasn’t the only rider to be caught out in the windy morning conditions, with Avintia’s Johann Zarco wiping out at Turn 14 early in the session.

Rookies Alex Marquez (Honda) and Iker Lecuona (Tech3) fell at Turn 2, with Quartararo dropping off his Petronas Yamaha SRT entry at high speed at Turn 8.

Quartararo’s teammate Morbidelli led the early running with a 1:50.533s before he was deposed by the 1:49.866s set by Viñales, who is the sole works Yamaha rider at Aragon following Valentino Rossi’s positive COVID-19 test.

The cold conditions prevented riders from executing a soft tyre time attack at the end of FP1, meaning Viñales held onto top spot.

The Spaniard once again led the way in FP2, with the warmer track temperatures seeing a more aggressive battle between the Yamaha entries.

Viñales set the early pace with a 1:50.688s, before Morbidelli (1:49.953s) and Quartararo (1:49.754s) hit back.

Morbidelli was the first to drop into the 1:48s bracket with a 1:48.992s 10 minutes into the session, before Mir lowered the marker to a 1:48.688s.

With 10 minutes remaining, Quartararo hit the front with a 1:48.406s before he improved to a 1:48.210s.

With colder temperatures expected for Saturday morning’s FP3, riders shot in quick times at the end of Friday’s session in a bid to progress into Q2.

There, Viñales broke away from his rivals with a 1:47.771s, with Quartararo and Morbidelli followed by Mir and LCR Honda’s Cal Crutchlow.

Aleix Espargaro (Aprilia) was sixth ahead of brother Pol (KTM), with Marquez eighth.

Ducati struggled, meanwhile, with Zarco the top runner for the Desmosedici in 11th, 1.135s down on Viñales.

Le Mans winner Danilo Petrucci was just 15th, behind team-mate Andrea Dovizioso (13th) and Pramac’s Jack Miller (14th). Francesco Bagnaia was slowest of the Ducati riders in 19th.

Saturday’s FP3 has been delayed by half an hour to allow for safer track temperatures, with the session to commence at 19:55 AEDT.