It was points leader Maverick Vinales who set the early benchmark of 1m47.669s in the opening 15 minutes of the 45-minute session, dislodging fellow Yamaha rider Jonas Folger from the top spot.

Vinales' time stood as the quickest until the closing five minutes, when the Ducati of Dovizioso lowered the bar to a 1m47.394s and Pirro slotted into second, 0.201s slower.

That knocked Vinales down to third, the Spaniard not improving thereafter and ending up just 0.005s clear of lead Tech 3 rider Johann Zarco in fourth.

Jorge Lorenzo overcame an apparent fuel pump issue to end up sixth fastest, 0.353s down on teammate Dovizioso, edged out by the year-old Avintia Ducati of Hector Barbera for a place in the top five.

Danilo Petrucci made it four GP17 Ducatis in the top seven a further two tenths behind, while Folger and Honda pair Marc Marquez and Cal Crutchlow completed the top 10.

Having been cleared to ride following last week's motocross crash, Valentino Rossi ended the first practice session of his home weekend in 15th place, 1.119s slower than Dovizioso.

Dani Pedrosa was another to miss out on a place in the top 10 in 13th aboard the second Repsol Honda, albeit less than a tenth behind Crutchlow's LCR machine.

Andrea Iannone was the lead Suzuki rider in 11th, Aleix Espargaro was best of the Aprilias in 14th, and Pol Espargaro led the KTM contingent in 20th, over two seconds off the pace.

Practice results:

Pos.	#	Rider	Bike	Time	Gap
1	4	Andrea Dovizioso	Ducati	1'47.394
2	51	Michele Pirro	Ducati	1'47.595	0.201
3	25	Maverick Viñales	Yamaha	1'47.669	0.275
4	5	Johann Zarco	Yamaha	1'47.674	0.280
5	8	Hector Barbera	Ducati	1'47.708	0.314
6	99	Jorge Lorenzo	Ducati	1'47.747	0.353
7	9	Danilo Petrucci	Ducati	1'47.962	0.568
8	94	Jonas Folger	Yamaha	1'47.974	0.580
9	93	Marc Marquez	Honda	1'47.980	0.586
10	35	Cal Crutchlow	Honda	1'48.194	0.800
11	29	Andrea Iannone	Suzuki	1'48.274	0.880
12	19	Alvaro Bautista	Ducati	1'48.289	0.895
13	26	Dani Pedrosa	Honda	1'48.291	0.897
14	41	Aleix Espargaro	Aprilia	1'48.394	1.000
15	46	Valentino Rossi	Yamaha	1'48.513	1.119
16	45	Scott Redding	Ducati	1'48.743	1.349
17	43	Jack Miller	Honda	1'49.119	1.725
18	53	Tito Rabat	Honda	1'49.123	1.729
19	76	Loris Baz	Ducati	1'49.526	2.132
20	44	Pol Espargaro	KTM	1'49.677	2.283
21	22	Sam Lowes	Aprilia	1'49.679	2.285
22	17	Karel Abraham	Ducati	1'49.754	2.360
23	38	Bradley Smith	KTM	1'50.686	3.292
24	50	Sylvain Guintoli	Suzuki	1'50.996	3.602