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. \"The track wasn\'t so bad, I expected the conditions to be much worse but in general it was ok,\" said Stoner. \"We finished quickest which is good but we\'ll have to wait until tomorrow for some real track time and with the conditions a little better and see where we are.\" 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, but the track seems pretty dirty,\" said the Spaniard. \"I feel good, we are at the top, close to Casey and we have improvements to come from the bike, the track and myself.\" 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.\" 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 1st session 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 2nd session 1. Thomas Luthi (SUI/Suter) 2:00.767, 2. Claudio Corti (ITA/Kalex) at 0.151, 3. Pol Espargaro (ESP/Kalex) 0.431, 4. Esteve Rabat (ESP/Kalex) 0.435, 5. Scott Redding (GBR/Kalex) 0.569 Moto3 1st session 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 2nd session 1. Maverick Vinales (ESP/FTR Honda) 2:08.160, 2. Zulfahmi Khairuddin (IND/KTM) at 0.498, 3. Danny Kent (GBR/KTM) 0.807, 4. Miguel Oliveira (POR/Honda) 0.819, 5. Axel Rins (ESP/Honda) 0.947