Toni Vilander led the way in an abbreviated opening practice in Dubai.
A 2:00.233 lap time set by the Ferrari factory driver late in the session put the No. 5 Spirit of Race entry atop the time sheets.
Vilander edged out the No. 458 GT Corse Ferrari 458 Italia GT3 of Pierre Kaffer by 0.604 seconds.
The No. 4 Fach Auto Tech Porsche 997 GT3 R of Sebastien Asch was third quickest overall and in the A6 class with a 2:00.903 lap time.
The 45-minute session was stopped halfway through due to a fire by the No. 144 GC Automobile BMW silhouette car of Jerome De La Chapelle.
Race officials stopped the clock but restarted the session with only 15 minutes remaining.
A second practice session is on tap for 1:15 p.m. local time.