Maverick Vinales completed a perfect opening day at the inaugural Moto3 grand prix in Qatar by leading both of Thursday's free practice sessions under the floodlights at Losail.
The Avintia FTR-Honda rider launched half a second ahead of Miguel Oliveira in the in final five minutes of FP2, then improved further on his last lap to rebuild that advantage after Malaysian Zulfahmi Khairuddin moved into a surprise second for AirAsia KTM.
Estrella Honda rider Oliveira then lost another position to factory Red Bull KTM rider Danny Kent, with Oliveira's rookie team-mate and reigning CEV 125cc champion Alex Rins finishing just behind him in fifth.
Rins was the final rider within one-second of four-time grand prix winner Vinales, with Kent's team-mate Sandro Cortese in sixth place and Aspar's Alberto Moncayo the leading Kalex-KTM competitor in seventh.
Final Moto3 free practice will be held on Friday evening.
Moto3, which features 250cc four-stroke machinery, has replaced the 125cc two-stroke class which ran from 1949-2011. The machinery change is instantly clear, with the deep four-stroke rumble replacing the two-stroke 'zing'.
Vinales beat his FP1 time by 1.5sec but is still some way off last year's 125cc pole time was a 2min 6.605sec. As in Moto2, Dunlop is the exclusive tyre supplier. Unlike in Moto2, open engine competition is allowed.
Thursday practice (2):
1. Vinales (FTR Honda) 2m 8.160s
2. Khairuddin (KTM) +0.498s
3. Kent (KTM) 0.807s
4. Oliveira (Honda) +0.819s
5. Rins (Honda) +0.947s
6. Cortese (KTM) +1.078s
7. Moncayo (Kalex KTM) +1.152s
8. Rossi (FTR Honda) +1.194s
9. Faubel (Kalex KTM) +1.341s
10. Antonelli (Honda) +1.342s
20. Webb (Mahindra) +2.699s