Doha: World champion Casey Stoner threw down the gauntlet to his rivals in impressive style on Thursday when he topped the first free practice for the season-opening Grand Prix of Qatar.

The Australian Honda rider clocked 1min 56.474sec to edge out former champion Jorge Lorenzo on a Yamaha with Ducati's Nicky Hayden almost half a second off the pace in third.

Seven-time MotoGP world champion Valentino Rossi, who has won this race three times, endured a miserable start to his season, managing just the 10th best time, over a second behind Stoner.

Stoner will start as favourite for Sunday's race to be held under the Losail circuit floodlights having won four times in the elite class in six visits.

Lorenzo said he was content with his lap on his new 1000cc machine after setting his best time in the closing minutes of the session.

"A quite good start, the track seems pretty dirty though, we are very far from the lap times of last year but that's the same for everybody," said the Spaniard.

"I feel good, we are at the top, close to Casey and we have improvements to come tomorrow from the bike, the track and myself. At the end we made a small change to gain some rear grip on all the corners which helped drop the lap time."

Rossi, who went without a race win for the first time in his career in 2011, admitted there was work to do on his Ducati machine if he was to match the pace of Stoner and teammate Hayden.

"It's the first practice and I used the hard tyre the whole session, trying to do a lot of laps in order to understand it," said the Italian.

"The new tyre is much better for warming up, so it's good for safety, but it started to slide a lot after some laps and made some of the understeer worse. We have to work with the setting and also the electronics.

"The soft will be important for Saturday (qualifying), but the hard will be the tyre for the race. Tomorrow we'll try to do better."

First free practice times:

MotoGP

1. Casey Stoner (AUS/Honda) 1:56.474, 2. Jorge Lorenzo (ESP/Yamaha) at 0.174, 3. Nicky Hayden (USA/Ducati) 0.450, 4. Ben Spies (USA/Yamaha) 0.508, 5. Dani Pedrosa (ESP/Honda) 0.656, 6. Cal Crutchlow (GBR/Yamaha) 0.921, 7. Alvaro Bautista (ESP/Suzuki) 1.038, 8. Andrea Dovizioso (ITA/Honda) 1.073, 9. Hector Barbera (ESP/Ducati) 1.438, 10. Valentino Rossi (ITA/Ducati) 1.440

11. Karel Abraham (CZE/Ducati) 1.465, 12. Stefan Bradl (GER/Honda) 2.460, 13. Randy de Puniet (FRA/Aprilia) 3.511, 14. Colin Edwards (USA/Suter-BMW) 3.570, 15. Michele Pirro (ITA/FTR-Honda) 3.848, 16. Aleix Espargaro (Aprilia) 4.246, 17. Ivan Silva (ESP/Kawasaki-FTR) 4.664, 18. Mattia Pasini (ITA/Aprilia) 4.787, 19. Yonny Hernandez (COL/Kawasaki-FTR) 4.802, 20. Danilo Petrucci (ITA/Ioda) 4.878

Moto2

1. Thomas Luthi (SUI/Suter) 2:01.284, 2. Esteve Rabat (ESP/Kalex) at 0.402, 3. Pol Espargaro (ESP/Kalex) 0.641, 4. Marc Marquez (ESP/Suter) 0.784, 5. Simone Corsi (ITA/FTR) 0.980

Moto3

1. Maverick Vinales (ESP/FTR Honda) 2:09.762, 2. Louis Rossi (FRA/FTR Honda) at 0.218, 3. Luis Salom (ESP/Kalex KTM) 0.539, 4. Miguel Oliveira (POR/Honda) 0.623, 5. Sandro Cortese (GER/KTM) 1.118

(Agencies)