Maverick Vinales © Gallo Images
Maverick Vinales continued to underline his impressive pace on the Yamaha YZR-M1 as he topped the timesheets in the first practice session of the Americas MotoGP in Austin, Texas.
The Spaniard was more than half a second ahead of his nearest competitor at the Circuit of the Americas.
Reigning world champion Marc Marquez held the early lead, while Honda duo Cal Crutchlow and Dani Pedrosa were also briefly in front.
But with 15 minutes to go, Vinales pulled out a 2m05.462s, putting him 0.073s ahead of Marquez - but he had more in the tank, posting an even quicker 2m04.923s to go 0.612s clear.
Marquez also improved late in the session, but only by a tenth, leaving Vinales comfortably on top.
Ducati looked to be having a bad day at the office until the last five minutes of the session, when Andrea Dovizioso improved from 12th to third, and Jorge Lorenzo from 16th to sixth.
Rookie Johann Zarco impressed to finish fourth for Tech 3, followed by Aspar's Alvaro Bautista, just inside a second down on the leader.
Pedrosa eventually settled in seventh, while Vinales' team-mate Valentino Rossi had to settle for eighth.
1 Maverick Vinales Movistar Yamaha MotoGP 2:04.923
2 Marc Marquez Repsol Honda Team 2:05.500
3 Andrea Dovizioso Ducati Team 2:05.604
4 Johann Zarco Monster Yamaha Tech 3 2:05.790
5 Alvaro Bautista Pull&Bear Aspar Team 2:05.833
6 Jorge Lorenzo Ducati Team 2:06.017
7 Dani Pedrosa Repsol Honda Team 2:06.109
8 Valentino Rossi Movistar Yamaha MotoGP 2:06.292
9 Aleix Espargaro Aprilia Racing Team Gresini 2:06.411
10 Danilo Petrucci Octo Pramac Racing 2:06.469
11 Cal Crutchlow LCR Honda 2:06.484
12 Jack Miller Team EG 0,0 Marc VDS 2:06.515
13 Scott Redding Octo Pramac Racing 2:06.646
14 Jonas Folger Monster Yamaha Tech 3 2:06.692
15 Hector Barbera Reale Esponsorama Racing 2:06.786
16 Andrea Iannone Team SUZUKI ECSTAR 2:06.824
17 Tito Rabat Team EG 0,0 Marc VDS 2:06.894
18 Loris Baz Reale Esponsorama Racing 2:07.127
19 Karel Abraham Pull&Bear Aspar Team 2:07.300
20 Alex Rins Team SUZUKI ECSTAR 2:08.006
21 Pol Espargaro Red Bull KTM Factory Racing 2:08.128
22 Sam Lowes Aprilia Racing Team Gresini 2:08.292
23 Bradley Smith Red Bull KTM Factory Racing 2:08.740