Maverick Vinales battles to win on his Yamaha debut
Maverick Vinales fought his way to the front, then held off the flying Ducati of Andrea Dovizioso, to win on his Yamaha debut at a wild Qatar MotoGP.
Rain arrived just minutes before the planned race start, promoting a 40-minute delay and reduction in race distance from 22 to 20 laps.
But when the action did begin it was worth the wait, with rookie Johann Zarco sensationally leading the early stages, only to fall from his Monster Yamaha Tech 3 machine on lap 7.
Dovizioso then took over, keeping his GP17 ahead of Honda's reigning champion Marc Marquez and Suzuki's Andrea Iannone - the pair spending the middle stages exchanging some close moves over second place.
Iannone lowsided out of podium contention (just as he had done for Ducati a year ago) on lap 11, while Marquez faded - almost certainly after a last-minute change to a softer front tyre.
Their places at the front were swiftly taken by Vinales and team-mate Valentino Rossi, who had worked their way up the order from fifth and seventh on the opening lap.
Vinales was able to reel in and then attack race leader Dovizioso. However the Ducati rider unleashed superior horsepower and repeatedly re-passed the Spaniard, with Rossi lurking in third.
But Vinales, dominant throughout winter testing and free practice, kept up his assault, pushing his M1 to the limit - smoke rising from his rear tyre - to gain enough space on the final lap and win by 0.461s.
Dovizioso had used the start delay to change from the medium to soft rear tyre, which probably cost him a little grip at the end. The Yamahas stuck with the medium, aiding their late charge.
Rossi finished one-second behind Dovizioso, but was delighted with a podium after such a difficult winter and practice. By contrast, Marquez was left 6.7s from victory and only just held off Repsol Honda team-mate Dani Pedrosa.
Aleix Espargaro enjoyed an excellent debut for Aprilia with sixth, ahead of Scott Redding (Pramac Ducati), Jack Miller (Marc VDS Honda), Alex Rins (Suzuki) and Jonas Folger (Monster Yamaha Tech 3).
Jorge Lorenzo's chances of a memorable Ducati debut effectively ended when he ran wide on the opening lap and dropped to 16th place.
The triple MotoGP champion recovered to eleventh.
Loris Baz (Avintia Ducati), Hector Barbera (Avintia Ducati), Karel Abraham (Aspar Ducati) and Tito Rabat (Marc VDS Honda) completed the point scorers.
KTM's first full MotoGP season began with Pol Espargaro and Bradley Smith 16th and 17th. Espargaro was four-seconds behind Rabat but six-seconds clear of his team-mate.
Aprilia rookie Sam Lowes was 17th and last on a night when 47seconds covered the entire field.
Like Marquez, Cal Crutchlow had used the start delay to switch from the hard to medium front tyre, a decision he also appeared to regret, falling twice from his LCR Honda.
Danilo Petrucci (Pramac Ducati) and Alvaro Bautista (Aspar Ducati) joined Zarco, Crutchlow and Iannone on the DNF list.