Ducati rider Andrea Dovizioso set the pace in the opening MotoGP practice session at the Red Bull Ring, heading points leader Marc Marquez by just under two tenths.
Marquez led almost the entirety of the session, but a late flyer from Dovizioso on soft tyres relegated the Honda rider to second place as Marquez had elected to stick with the medium compound instead.
Marquez had set the initial pace on the opening run of the session, ending up on a 1m24.338s time that left him five tenths clear of nearest rival Jack Miller.
The Honda rider set that effort by following Maverick Vinales and Marquez ultimately overtook the Yamaha rider only to then run through the gravel after getting his braking wrong at the Turn 4 right-hander.
Late into his second run, Marquez improved to a 1m24.218s and retained a big advantage over the chasing pack until the final minutes, when Dovizioso lapped within half a tenth of his benchmark.
As the chequered flag flew, Dovizioso fired in a 1m24.033s lap to snatch the FP1 leading time from Marquez.
Vinales ended up third, a quarter of a second down on Dovizioso.
Pramac Ducati rider Jack Miller - who is currently at the centre of an emerging 2020 rider market saga that involves the injured Jorge Lorenzo - snatched fourth place at the end.
Valentino Rossi was fifth on the second of the Yamahas, edging out the satellite Petronas bike of Fabio Quartararo by 0.002s.
Alex Rins, the sole Suzuki rider this weekend with Joan Mir absent, took seventh.
Johann Zarco led the local KTM outfit's efforts in eighth place, as LCR Honda's Takaaki Nakagami and Tech 3 KTM's Miguel Oliveira completed the top 10.
Oliveira's team-mate Hafizh Syahrin was the only rider to crash during the session, suffering a near-highside at the penultimate corner and taking a hit to the abdomen.
He received assistance on-site and was taken to the medical centre for a check-up.
Aleix Espargaro was the top Aprilia rider in 12th, beatings the likes of works Ducati rider Danilo Petrucci in 14th and Lorenzo's Honda stand-in Stefan Bradl in 19th.
Free practice one result
|4||Jack Miller||Pramac Ducati||Ducati||0.327s||21|
|6||Fabio Quartararo||Petronas Yamaha||Yamaha||0.438s||23|
|9||Takaaki Nakagami||LCR Honda||Honda||0.828s||22|
|10||Miguel Oliveira||Tech3 KTM||KTM||0.891s||21|
|11||Cal Crutchlow||LCR Honda||Honda||0.929s||22|
|13||Francesco Bagnaia||Pramac Ducati||Ducati||0.963s||20|
|16||Karel Abraham||Avintia Ducati||Ducati||1.289s||20|
|17||Franco Morbidelli||Petronas Yamaha||Yamaha||1.352s||23|
|20||Hafizh Syahrin||Tech3 KTM||KTM||1.700s||16|
|21||Tito Rabat||Avintia Ducati||Ducati||1.912s||26|