Marc's brother Alex finished third to make it two brothers on a MotoGP podium for the first time in 27 years since Japan's Nobuatsu Aoki and Takuma Aoki took second and third at the Imola Grand Prix.
Martin had smashed the lap record to clinch pole and then win the sprint on Saturday to take a 15-points lead in the championship but Bagnaia's fourth consecutive victory moved him 10 points clear of Martin in the championship.
More to follow.