Maro Engel laid down a lap of 2min 18.948secs as the chequered flag fell to claim fastest time from his team mate Raffaele Marciello, 2min 18.969.
Mercedes-Benz seized the top three positions in the 30minute session.
Edoardo Mortara, arguably the most successful Macau competitor in the field with two F3 and three GT victories, rounded out the top three with a 2min19.105secs in his Mercedes AMG Team Driving Academy AMG GT3.
It was Mortaro’s first time in Mercedes-Benz at Macau.
Engel’s fastest lap emphasised the benefit of experience at the Macau circuit.
He has specialised in Mercedes-Benz’ assault on both the FIA GT championship and the races which have preceded it.
Twice Formula 3 winner Felix Rosenqvist who has swapped to the GT category for the first time was sensational with fourth fastest in the only Ferrari in the field on 2min 19.249secs.
Macau debutante Robin Frinjs (Audi Sport Team WRT R8 LMS) was equally sensational claiming fifth fastest in his first ever sighting of the tough, narrow 6.12km track.
Seven makes are contesting the FIA GT World Cup.
Fastest BMW was Augusto Farfus (Schnitzer M6) in eighth position
Darryl O’Young claimed honours for Porsche in 10th position from Craft Bamboo team mate, defending FIA GT World Cup champion Laurens Vanthoor, 12th.
Mirko Bortolotti (FF Racing Team by ACM) was 13th fastest for Lamborghini and Renger Van der Zande was 19th on debut in the Honda NSX GT3.