Pole-sitter Bezzecchi lost out on a sprint podium after a collision with teammate Luca Marini, eventually finishing fifth, but on Sunday there was no rider in the chasing pack who could match the determined Italian's pace up front.
Pramac Racing rider and sprint winner Jorge Martin, who risked a penalty by unzipping his leathers, finished second while Yamaha's Fabio Quartararo completed the podium after the two were involved in a tense battle on the final lap.
World championship leader Bagnaia seemed to be cruising in second place but lost his balance on turn five with eight laps to go, allowing Martin to move up to second and close the gap to 13 points while Bezzecchi is 44 points behind.
"I'm very happy, it was a tough race, very long. After yesterday, unfortunately I was hit in the start and today I wanted revenge," Bezzecchi said in a pit lane interview.
"I started well. I got on the lead early and then I was focused. I enjoyed this track."
Bagnaia initially took the lead on the straight at the Buddh International Circuit, with Martin braking late and going wide in a desperate but ultimately futile attempt to keep the faster Ducati behind him.
But Bezzecchi also capitalised to move up to second before the pole sitter moved into the lead at the end of the first lap and his searing pace allowed the Italian to extend his lead to more than two seconds after four laps.
MARTIN MOVES UP
That was the signal for Martin to risk an overtake on Bagnaia with a lunge on the inside and he made it stick, much to Bagnaia's surprise as the championship leader pulled out of a quick turn to avoid a collision.
But with nine laps to go, Martin seemed to be struggling with his front tyre and that opened the door for Bagnaia to retake second place before the Italian crashed.
Martin was visibly struggling in the hot and humid conditions and after keeping Quartararo at bay, he got down on his knees in the pit lane as his team poured bottles of water down his racing suit.
The race was shortened by three laps on the request of riders due to hot and humid conditions during practice sessions.
The Spaniard later fainted and was propped up at the fence below the podium as MotoGP's medical director assessed him, but he was back on his feet after taking on some fluids.
Six-time MotoGP champion Marc Marquez looked set to battle for third but the Honda rider fell on turn one on the fifth lap and eventually finished ninth.
