Andrea Dovizioso scored his first MotoGP win for over seven years by defeating Valentino Rossi in a straight fight at Sepang, mastering the wet conditions as other leading contenders fell by the wayside.
A heavy shower just prior to the start saw the race delayed by 20 minutes and shortened by one lap to 19. The top six on the grid opted for the same tyre choice of wet mediums front and rear.
The early laps were characterised by some frenetic tussling, as Jorge Lorenzo scorched into an early lead but quickly dropped back to the rear of a six-bike train led by Rossi and Andrea Iannone.
Rossi and Iannone exchanged blows numerous times as poleman Dovizioso hung back in third place ahead of Marc Marquez, Cal Crutchlow and Lorenzo, who steadily lost touch with the leading pack.
The next rider to drop out of the lead fight was Crutchlow with a crash at Turn 2 on Lap 12, while Marquez fell later on the same lap at Turn 11.
That left it as a three-way fight between Rossi and the Ducati riders, until Iannone hit the deck at Turn 9 just a lap after the two Honda men had fallen out of contention.
Rossi therefore led Dovizioso with a sizable gap back to Lorenzo in third place, but the decisive move came at the start of the 15th lap as Rossi ran wide and allowed Dovizioso into a lead he would never relinquish.
The Ducati rider stretched out a lead of four seconds over Rossi, finally crossing the finish line 3.115s ahead to clinch his first win since Donington Park 2009 and his first as a Ducati rider. He also became the ninth winner in 17 MotoGP races this year.
Nonetheless, seven-time MotoGP champ Rossi confirmed runner-up spot in the 2016 points race.
Some 8.8s behind Rossi, finished Lorenzo on the second factory Yamaha, with a similar margin splitting the Spaniard from leading independent rider Hector Barbera in fourth.
Behind the leading sextet, Avintia Ducati riders Loris Baz and Barbera steadily climbed to seventh and eighth places, and their battle became one for fourth as riders ahead dropped out.
Maverick Vinales brought home the best of the Suzukis sixth, ahead of the Aprilia of Alvaro Bautista and the top Honda of Marc VDS rider Jack Miller in eighth.
Completing the top 10 were Pol Espargaro (Tech 3 Yamaha) and Danilo Petrucci (Pramac Ducati), followed by Marquez, who remounted his Repsol Honda to clinch five points for 11th place.
Aleix Espargaro (Suzuki) finished 13th after opting for a soft rear tyre, running with the leaders at the start but running well wide at Turn 1 on the second lap and never recovering.
The only other rider to crash besides Crutchlow, Marquez and Iannone was Stefan Bradl on the second of the Aprilias.