Unlike the sprint, Martin made a great start as he attempted to take the lead heading into turn one.
However, the Pramac rider was too late on the brakes as he ran wide which allowed four riders, including title rival Bagnaia to come through.
The polesitter also lost two places as team-mate Bastianini and Alex Marquez got through on the reigning world champion.
On lap three Martin made his first move on Bagnaia, but the latter made sure he didn’t succumb to the pressure.
Bagnaia swept back underneath Martin on the exit of turn 14 before doing the same on lap four.
Joan Mir, who crashed during the sprint, went down on lap five of the main race while Miguel Oliveira suffered the same fate one lap later.
After crashing four times on Friday, Aleix Espargaro suffered another fall in the Grand Prix at turn nine.
As the race continued to develop, so did the gap between Bagnaia and Martin as a margin of two seconds separated the pair with 12 laps gone.
There was a fall for Brad Binder on lap 12 as the factory KTM rider went down at turn ten whilst battling for eighth.
A lap later and it was another troublesome moment for Honda as Takaaki Nakagami crashed at turn nine.
Fabio Quartararo continued his brilliant ride with a move on Marco Bezzecchi for P5. His latest overtake came after distancing himself from Jack Miller and Fabio Di Giannantonio.
Olivia Martin is a dedicated sports journalist based in the UK. With a passion for various athletic disciplines, she covers everything from major league championships to local sports events, delivering up-to-the-minute updates and in-depth analysis.
