Huff, who has the best WTCC winning record in Macau, enjoyed the best of a late flurry of activity to clock the fastest time of 2:32.169 before going on to better his own time and further improve to 2:32.147 on the following lap.
The dying moments of the session provided plenty of improvements.
Norbert Michelisz’s Honda Civic set the second fastest lap of 2:32.218, beating Yvan Muller’s Chevrolet Cruze (2:32.372) and the other Honda of Tiago Monteiro (2:32.693).
Pepe Oriola ranked fifth (2:32.780) with Stefano D’Aste, the best of the BMW drivers and Yokohama Trophy competitor despite of an early collision with Campos Racing’s newcomer Konstantins Calko, in sixth (2:33.314).
Tom Chilton, Tom Coronel, James Thompson and Medhi Bennani respectively round out the top 10.
Michael Soong toped the Asia Trophy competitors in 22nd position overall, followed by Henry Ho in 23rd.
Friday morning will see the WTCC field take to the track for two 30-minute free practice sessions, before the two-stage qualifying begins in the afternoon.