Starting from pole for a perfect fourth time this season, Marc Marquez quickly retaliated when briefly overtaken by younger brother Alex at the end of Lap One, before pulling the pin, building a gap and taking a convincing victory.
He was joined on the podium by Alex Marquez in second.
Fabio Quartararo finished fifth, Ai Ogura seventh, Pecco Bagnaia eighth and Maverick Vinales tenth; all Alpinestars riders.
