Ducati's Marquez had a chance to retain his crown this weekend after winning Saturday's sprint race but needed his closest rival, Jorge Martin, to finish out of the points.
Martin, Bezzecchi's teammate at Aprilia, finished seventh and is still in contention even though he is 60 points off the pace with two race weekends remaining.
But Marquez could claim a record-equalling eighth premier-class title, one more than his great rival Valentino Rossi, if he finishes two points ahead of Martin in the Portimao sprint in two weeks' time.
"(My strategy) was just to try to manage the race the first five laps," said Marquez.
"I saw that in one part of the race I was super fast, but I knew that riding on that riding style, I was eating the front tyre.
"Third position was (would have been) okay, but I saw that Fernandez was struggling, so you never know; I attack and four points more."
Pole-sitter Bezzecchi claimed his sixth GP win of the season to cut the gap separating him from Marquez to 74 points.
However, the Italian, who is third in the championship standings, effectively has no chance of winning his first world title as that gap is the same as the number of points that remain available.
Bezzecchi was undone by crashing out of the sprint race when trying to overtake Marquez in a desperate attempt to put pressure on the Spaniard.
"It feels amazing. I'm very happy. It was the performance we deserved," said Bezzecchi.
"It's been a fantastic weekend for us. I've been super quick and super comfortable on the bike.
"It's a shame for yesterday, but it's part of the game and to bounce back like this makes everything even better."
Martin couldn't quite emulate his heroics from Saturday, when he shot up from 11th on the grid to nearly overtake eventual winner Marquez, before eventually finishing third.
But racing this weekend for the first time since suffering a broken right wrist, Martin was given a warm round of applause from his team after keeping the title race alive.