Australian Jack Miller had his best race of the season but was just edged out in a titanic last lap duel by Franco Morbidelli at the Valencia Grand Prix while Joan Mir clinched his maiden MotoGP crown.
Suzuki rider Mir became the Japanese team's first world champion in two decades with his seventh-placed finish.
He had begun the race with a 37-point lead over his closest challengers Fabio Quartararo, of Petronas Yamaha, and Suzuki teammate Alex Rins.
His fourth successive top-10 finish saw him emulate American Kenny Roberts Jr., who won the riders' championship for Suzuki in 2000.
With one race to go, Mir has an unassailable 29-point lead over Petronas Yamaha's Morbidelli, who withstood a spirited challenge from Pramac Racing's Miller to seal his third victory of the season.
Going bike-to-bike over a thrilling last lap, the Italian just edged out Miller by 0.093 seconds, leaving the Australian to reflect on equalling his best effort of the year, a runner's up spot at the Styrian Grand Prix in August.
This was an even better effort, though, as the 25-year-old Queenslander also recorded the race's fastest lap. He is currently eighth in the championship overall.
Pol Espargaro, of KTM, completed the podium.
Mir's Suzuki team mate Rins, who qualified in 14th, stormed out of the blocks to make up seven spots in the first two laps as he battled to keep his title hopes alive but the Spaniard managed only a fourth-place finish, leaving him 33 points behind Mir.
Quartararo's title challenge ended with a whimper as the Frenchman crashed out of the race on lap nine after starting from 11th.