Rossi wins opening race as Stoner chokes
Rossi, on a Yamaha, won by 1.022sec from teammate Jorge Lorenzo while his Italian compatriot Andrea Dovizioso, riding a Honda, was 1.865sec off the pace.
Australia's Stoner, who was bidding for a fourth successive win at the floodlit desert venue, crashed out on the fifth lap having started on pole position on his Ducati.
Stoner, who had dominated practice and qualifying at the season-opening weekend, was passed by Dani Pedrosa (Honda), who had started in seventh place, at the first turn.
Stoner reclaimed the lead but his race ended on the fifth lap of the 22-lap race when he lost the front of his machine.
That elevated Rossi to first place, with Dovizioso and Nicky Hayden, on another Ducati, behind him.
Dovizioso briefly passed Rossi before the world champion hit back.
Lorenzo then made his move and went past Hayden before also squeezing out Dovizioso at the start of the final lap.
Qatar Grand Prix Results
1. Valentino Rossi (ITA/Yamaha) 42:50.099
2. Jorge Lorenzo (ESP/Yamaha) at 1.022
3. Andrea Dovizioso (ITA/Honda) 1.865
4. Nicky Hayden (USA/Ducati) 1.876
5. Ben Spies (USA/Yamaha) 3.903
6. Randy de Puniet (FRA/Honda) 9.322
7. Dani Pedrosa (ESP/Honda) 16.508
8. Colin Edwards (USA/Yamaha) 19.867
9. Loris Capirossi (ITA/Suzuki) 20.893
10. Hiroshi Aoyama (JPN/Honda) 21.100