Stefan Bradl carried his pre-season form into the first practice session of 2011 by going quickest in the first Moto2 action of the new season.
The Viessman Kiefer Team rider set a time of 2:02.463 to edge a session-long battle with Scott Redding, who made an encouraging start by taking 3rd place.
The Brit is starting his second season with the Marc VDS Team and traded times with the German before pitting in the dying minutes.
The two were split by 125cc World Champion Marc Marquez who briefly topped the timesheets, before finishing just over half a second off Bradl's pace.
Thomas Luthi and Andrea Iannone were next up with Forward Racing's Jules Cluzel completing the top six.
2010 series runner-up Julian Simon set the early pace but slipped back to 11th, over a second off the pace.
125cc graduate Bradley Smith made a quiet start in the 600cc class with a time of 2:04.891 seeing him finish down in 20th place, with fellow Brit Kev Coghlan struggling down in 35th, just ahead of the home pair Nasser Al Malki and Mashel Al Naimi.
Two of the riders who have made the switch from MotoGP had contrasting starts. Aleix Espargaro made a solid start in 9th while Mika Kallio could only manage 23rd, well down on teammate Redding.
Second Practice for the Moto2 Grand Prix of Qatar will take place at 18.50 GMT ahead of Sunday's season opener.