Yamaha rider Jorge Lorenzo started his MotoGP title defence in the best possible fashion, withstanding an early Ducati challenge to win the Qatar Grand Prix.
Polesitter Lorenzo changed from a medium-compound rear tyre to a soft on the grid and kept the lead off the line, only for the Ducatis of Andrea Iannone and Andrea Dovizioso to blast past on the main straight at the end of the first lap.
With Lorenzo lacking the straightline speed to get back past them, Iannone led a five-rider pack before he and his team-mate started to fight with each other.
Dovizioso got down the inside of Iannone at Turn 1 on lap six, but Iannone went for a switchback and the pair made light contact at the apex.
Iannone reclaimed the lead but was passed again by Dovizioso, before Iannone's race ended when he fell at Turn 6 later in the lap.
Dovizioso kept Ducati in front for another three laps, until Lorenzo reclaimed top spot with a bold move around the outside of the Italian.
Crucially, Lorenzo stayed ahead down the long straight the next time around and was not headed again over the remaining 14 laps.
He was initially at the front of a closely-matched quartet, with Dovizioso followed by Honda's Marc Marquez and the second Yamaha of Valentino Rossi.
Lorenzo gradually built a lead of half a second and when Marquez forced his way past Dovizioso with three laps to go, Lorenzo was 1.159 seconds clear.
The race leader then immediately quashed any thoughts of Marquez mounting a challenge for the win by setting the fastest lap of the race, and he eventually crossed the line two seconds clear.
Dovizioso got back ahead of Marquez, who then challenged again for second at the last corner, but the Ducati had enough to secure second.
Rossi nearly pipped Marquez to take the final podium finish, falling just 0.100s short.
Dani Pedrosa and Maverick Vinales had quiet races to finish fifth and sixth, a further 12 seconds behind, Suzuki rider Vinales falling from the front row of the grid down to seventh early, due to a slow start.
Cal Crutchlow was the leading satellite rider in the early stages, despite LCR Honda's engine-braking issues, but crashed at Turn 4 on lap seven.
That paved the way for Pol Espargaro to finish seventh for Tech3 Yamaha, holding out a late challenge from team-mate Bradley Smith, who flew in the closing laps.
Hector Barbera was ninth, while Scott Redding completed the top 10.
Aprilia took 13th on the debut of its new RS-GP with Alvaro Bautista, while team-mate Stefan Bradl crashed out.
RESULTS - 22 LAPS:
|7||Pol Espargaro||Tech3 Yamaha||22||18.629s|
|8||Bradley Smith||Tech3 Yamaha||22||18.652s|
|9||Hector Barbera||Avintia Ducati||22||21.160s|
|10||Scott Redding||Pramac Ducati||22||24.435s|
|12||Eugene Laverty||Aspar Ducati||22||41.756s|
|14||Jack Miller||Marc VDS Honda||22||41.982s|
|15||Tito Rabat||Marc VDS Honda||22||54.953s|
|-||Loris Baz||Avintia Ducati||8||Retirement|
|-||Cal Crutchlow||LCR Honda||6||Retirement|
|-||Yonny Hernandez||Aspar Ducati||1||Retirement|
|-||Danilo Petrucci||Pramac Ducati||0||Withdrawn|