Reigning MotoGP champion Marc Marquez topped the first practice session for the Italian Grand Prix at Mugello ahead of Ducati's Danilo Petrucci.
Honda's Marquez set his best lap - a 1m47.558s - just 10 minutes into the 45-minute session.
In doing so he improved on the 1m47.804s set by Ducati tester Michele Pirro, who is making the first of three planned wildcards this year on a third factory GP19 this weekend and was the early FP1 pacesetter.
Pirro's time looked to be good enough for second until right before the chequered flag, when it was surpassed by Petrucci's effort of 1m47.751s.
Petronas SRT rider Fabio Quartararo was another late improver, setting a 1m47.811s on the best of the Yamahas to go fourth-fastest.
Aleix Espargaro, whose best lap was aided by a tow from Marquez in the early running, was fifth-fastest for Aprilia, although his session was curtailed by a technical problem that forced him to park up at the end of the straight.
Jack Miller ended up sixth on the Lamborghini-liveried Pramac Ducati, followed by Takaaki Nakagami (LCR Honda), KTM rider Pol Espargaro and the second LCR bike being ridden by Cal Crutchlow.
Ducati's Andrea Dovizioso was 0.656s off the pace in 10th, while Valentino Rossi was the quicker of the works Yamahas in 12th, just behind Alex Rins' (Suzuki).
Maverick Vinales finished 14th, 0.036s slower than Rossi, on the second factory M1.
Jorge Lorenzo continued to struggle with his Honda and finished 18th, a little under a second adrift of Marquez.
Johann Zarco was 20th on his factory KTM in what was largely an incident-free session.
|4||Fabio Quartararo||Petronas Yamaha||1m47.811s||0.253s||21|
|6||Jack Miller||Pramac Ducati||1m47.814s||0.256s||16|
|7||Takaaki Nakagami||LCR Honda||1m47.925s||0.367s||19|
|9||Cal Crutchlow||LCR Honda||1m48.109s||0.551s||18|
|15||Franco Morbidelli||Petronas Yamaha||1m48.421s||0.863s||20|
|16||Karel Abraham||Avintia Ducati||1m48.427s||0.869s||18|
|17||Francesco Bagnaia||Pramac Ducati||1m48.532s||0.974s||18|
|21||Tito Rabat||Avintia Ducati||1m49.216s||1.658s||18|
|22||Hafizh Syahrin||Tech3 KTM||1m49.857s||2.299s||16|
|23||Miguel Oliveira||Tech3 KTM||1m49.870s||2.312s||17|