Ducati dominated the action at the Circuit of the Americas, with factory rider Jack Miller taking third place.
The result poses questions for Ducati, who are yet to decide on their rider line-up for next year, with Miller and Bastianini both in contention for the second seat alongside Francesco Bagnaia.
Elsewhere, Marquez made a stunning charge back through the field to finish in sixth, with an enthralling battle with reigning world champion Fabio Quartararo in the late stages.
Suzuki maintained the consistency they’ve shown so far this season, with Alex Rins taking second place with 2020 world champion Joan Mir in fourth.
In the latest Tank Slappers Podcast, Autosport’s Lewis Duncan and Motorsport.com’s Oriol Puigdemont review all the weekend’s action.
