The first Moto2 practice session of the 2012 season ended with Thomas Luthi on top the timesheets, after Thursday evening's opening session for the Qatar night race at Losail.
Interwetten Suter rider Luthi, who took an overdue first Moto2 win at Sepang last season, knocked session leader Esteve Rabat from the head of the timesheets by 0.402sec on his 14th and final lap.
Luthi's time of 2min 1.284sec was within 0.3sec of the official race lap record.
Rabat and Pons Kalex team-mate Pol Espargaro finished the session in second and third, with 2011 runner-up Marc Marquez (Suter) rising to fourth on his final lap.
FTR's Simone Corsi (FTR) and Speed Master's Andrea Iannone (Speed Up) were the remaining riders within one-second of Luthi.
Mika Kallio (Kalex), Scott Redding (Kalex), Mike di Meglio (Speed Up) and Takaaki Nakagami (Kalex) completed the top ten, with Bradley Smith the leading Tech 3 rider in eleventh.
Returning former champion Toni Elias was just 19th fastest for Aspar Suter.
Second Moto2 practice will take place later this evening.
2012 is the third year of the 600cc grand prix world championship class, which features a control Honda engine and Dunlop tyres.