Pole-sitter Andrea Dovizioso survived a battle of the fittest to triumph ahead of Valentino Rossi in a thrilling, rain-affected Malaysian MotoGP and end his seven-year wait for a win.
Ducati's Dovizioso became the ninth different winner in MotoGP this season, staying on his bike when others did not and pouncing on a mistake by Rossi with four laps remaining at Sepang International Circuit.
Rossi's second-place finish was still enough for him to clinch a runner-up placing in the world championship.
Sunday's race was delayed by 20 minutes due to torrential rain, with the start pushed back to 15:30pm local time and the number of laps trimmed by one to 19.
Last season's world champion Jorge Lorenzo was among several riders who appeared reluctant to take to the track in the wet conditions but when the race eventually got underway, fans were treated to a dramatic spectacle.
There were five riders battling it out for top spot, in Andrea Iannone, Rossi, Dovizioso, world champion Marquez and Cal Crutchlow.
Yet that battle was suddenly reduced to two after Iannone, Marquez and Australian GP winner Crutchlow dramatically fell off their bikes in quick succession and out of the podium places.
As a result, Rossi and Doviziosio were left to contest victory and just as the former looked set pull clear, he ran wide at turn one to gift his countryman a famous triumph in Malaysia.
Rossi's team-mate Lorenzo clinched third, ahead of Hector Barbera and Loris Baz.