Thomas Luthi ruled both of Thursday's Moto2 free practice sessions in Qatar, setting his best time of the night on his final lap of the second session.
The Interwetten Suter rider slashed half-a-second from his FP1 pace to dip under the official race lap record and end FP2 0.151sec clear of Italtrans Kalex rider Claudio Corti.
Corti, who had edged out last year's Sepang Moto2 winner Luthi to lead the final pre-season test, was the first of five successive Kalex riders, being followed on the timesheets by Pol Espargaro, Esteve Rabat, Scott Redding and Mika Kallio.
2011 title runner-up Marc Marquez was the second-best Suter in seventh place, 0.688sec from Luthi, with Mike di Meglio looking much more comfortable on the Speed Up than he had on last year's Tech 3 bike in eighth.
Corti's rookie tam-mate Takaaki Nakagami was top ten in both sessions, while former champion Toni Elias advanced from 19th in FP1 to tenth in FP2 for Aspar Suter.
Third Moto2 practice will take place on Friday evening.
2012 is the third year of the 600cc grand prix world championship class, which features a control Honda engine and Dunlop tyres.
Thursday practice (2):
1. Luthi (Suter) 2m 0.767s
2. Corti (Kalex) +0.151s
3. Espargaro (Kalex) +0.431s
4. Rabat (Kalex) +0.435s
5. Redding (Kalex) +0.569s
6. Kallio (Kalex) +0.593s
7. Marquez (Suter) 0.688s
8. di Meglio (Speed Up) +0.757s
9. Nakagami (Kalex) +0.863s
10. Elias (Suter) +1.059s
15. Smith (Tech 3) +1.314s
27. Rea (Moriwaki) +3.442s