MotoGP rookie Marc Marquez defied sandy conditions, and the odd drop of rain, to outpace the Yamaha riders during the first of Friday's free practice sessions in Qatar.

Just as on Thursday, Valentino Rossi led the majority of the session only to lose out in the final five minutes.

Yesterday it was M1 colleagues Jorge Lorenzo and Cal Crutchlow who pipped the Italian. Lorenzo repeated the feat this evening - before Honda rookie Marquez shot from ninth to first with the best lap of the weekend!

Moto2 champion Marquez, the top RCV rider but +0.591s on Thursday, concluded the session with a 0.268s advantage over Lorenzo, followed by Rossi (+0.328s), Crutchlow (+0.692s) and LCR Honda's Stefan Bradl (+0.780s).

Of those, only Marquez and Bradl - second to Rossi during the middle stages of the 45-minutes - were able to beat their best FP1 lap time. Marquez ran on at turn one moments after setting his best lap.

Lorenzo was reported to have again tried the latest Yamaha chassis, which Rossi decided against after testing at Jerez.

Andrea Dovizioso was again the top Ducati rider, this time in sixth place and 1.3s from Marquez.

Marquez's team-mate and triple title runner-up Dani Pedrosa, eighth after struggling with corner entry problems on Thursday, was again seen running off-track on his way to seventh this evening (+1.4s).

Nicky Hayden (Ducati), Ben Spies (Pramac Ducati) and Alvaro Bautista (Gresini Honda) completed the top ten, followed by rookies Bradley Smith (Tech 3 Yamaha) and Andrea Iannone (Pramac Ducati).

Aspar's Aleix Espargaro again set the CRT pace, in 13th overall (+2.154s).

Rain drops threatened to delay the start of the session, but the moisture didn't develop into anything stronger and the green lights were illuminated on time.

Clouds of fine sand were seen billowing behind the bikes during their opening laps, proving that the asphalt was dry - but very dirty - due to the strong wind blowing sand onto the track.

Third practice takes place later this evening, after which the ten fastest riders will automatically be eligible for the second and final part (Q2) of Saturday's new qualifying system.

Those outside the top ten must take part in Q1, where only the two fastest riders will be allowed to join Q2.

Friday practice (1):
1. Marc Marquez
2. Jorge Lorenzo
3. Valentino Rossi
4. Cal Crutchlow
5. Stefan Bradl
6. Andrea Dovizioso
7. Dani Pedrosa
8. Nicky Hayden
9. Ben Spies
10. Alvaro Bautista
11. Bradley Smith
12. Andrea Iannone
13. Aleix Espargaro
14. Yonny Hernandez
15. Hector Barbera
16. Randy De Puniet
17. Karel Abraham
18. Danilo Petrucci
19. Hiroshi Aoyama
20. Lukas Pesek
21. Colin Edwards
22. Claudio Corti
23. Bryan Staring
24. Michael Laverty