Martin Rump and the No. 18 KCMG Audi R8 LMS led the way on Friday in the first day of Free Practice for the inaugural round of the Blancpain GT Series Asia at Sepang.
The Estonian driver reeled off a 2:03.528 midway through the second session of the day, as conditions improved at the Malaysian circuit.
This came after the first session early on Friday afternoon was affected by torrential rain.
GruppeM driver Raffaele Marciello posted a 2:17.584 at the end of Free Practice 1, putting the No. 999 Mercedes-AMG GT3 top in the wet conditions.
Martin Kodric was second-fastest in the Vincenzo Sospiri Raing Lamborghini Huracan GT3, just 0.099 seconds down on Marciello.
Impressively, the top 13 runners were covered by less than one second in FP1.
As Rump set the fastest time of the day with a drier track in Free Practice 2, Will Stevens took second for the Team WRT entry, 0.257 seconds slower than the Champion-backed KCMG car.
GruppeM showed its might in the dry conditions as well, taking third and fourth in FP2 with its pair of Mercedes, while the Spirit of Race and BBT Ferrari 488 GT3s completed the top six.
Ringo Chong was the fastest driver out of the GT4 contingent, lapping the circuit in 2:21.202 in the HubAuto Racing Porsche Cayman GT4 Clubsport MR.
Free Practice 3 is scheduled for 8:15 a.m. local time on Saturday morning, with qualifying at 10:40 a.m. Race 1 will follow at 3:10 p.m.