Austin MotoGP king Marc Marquez surprised no-one by topping the opening free practice today but he was pushed hard by countryman Maverick Vinales who tralied the Repsol Honda man by only 0.078s.
Marquez set the timesheets on fire early doors and then upped his pace to a 2'05.311 on the insanely bumpy Texas track using the soft front/medium rear Michelin combination.
Vinales had problems of his own with the bumps, getting punted out of the seat down the fast Hayden Hill turn but he was able to keep a rein on the 2019 championship leader, using the same tyre combination.
Pramac Ducati's Jack Miller ended in third place and the top Desmosedici runner. Also on soft/medium combo, Miller put in a 2'05.936 which was 0.625s off the pace.
Andrea Dovizioso rescued fourth place late on after a mechanical problem saw him stuck a long way from the pits. The works Ducati man then slotted in soft Michelins all round to ensure a decent lap time of 2'05.953 for fourth place.
Valentino Rossi finished in fifth place and seven-tenths off the pace, using the same soft/medium Michelins as his Monster Yamaha team-mate Vinales.
Pol Espargaro put in a late charge for sixth place while rookie Fabio Quartararo hopped into seventh on his Petronas Yamaha with his last lap.
Cal Crutchlow was eighth, Aleix Espargaro ninth and Aprilia's Andrea Iannone completed the top ten.
Franco Morbidelli, on the second Petronas R1, finished 1.418s off the pace in 11th with Karel Abraham powering the GP18 to 12th. Danilo Petrucci was 13th ahead of the two works Suzukis.
It was not a good session for Jorge Lorenzo, who ended in 18th behind Johann Zarco and Taka Nakagami.
