Bagnaia crossed the line just ahead of Aprilia's Maverick Vinales in second, while Yamaha's Fabio Quartararo, the 2021 world champion, finished third.
Champion Bagnaia is back on top of the riders' standings with 346 points, with Martin (328) in second and Bezzecchi (283) in third.
Pramac Racing's Martin, who took the championship lead on Saturday after winning the sprint, started from the second row in sixth place but did not stay there long, rocketing off the line in hot conditions to take the lead after the very first turn.
But with the Spaniard cruising with a comfortable lead of over two seconds, his bike went from under him and he was dumped in the gravel, leaving him holding his head in his hands in disbelief at spurning the gilt-edged opportunity.
