Audi continued its session-topping pace in the first-ever twilight Bathurst 12 Hour practice session.
The times dipped into the 2:03s bracket for the first time on Friday as temperatures dropped.
Top honours went to Kelvin van der Linde (#74 Audi), who recorded a 2:03.956s.
Supercars ace and fellow Audi driver Chaz Mostert was second all told, some 0.39s behind.
The session, which began at 5:05pm local time, quickly descended into darkness.
However, the session was halted just 10 minutes in due to debris at The Chase.
Cars returned to the track after a nine-minute stoppage, and the times began to tumble.
The fastest of all through the runs was van der Linde, who set the first 2:03s lap of the weekend.
South African van der Linde, who later handed over to Nathanael Berthon, recorded a 2:03.956s.
Maro Engel (#91 Mercedes-AMG) went purple in the first sector as the chequered flag flew.
The German driver slotted into third in his Craft-Bamboo Mercedes, just behind Mostert’s #65 Audi.
Markus Winkelhock was fifth in the #777 Audi, which topped Practice 1 thanks to Ricardo Feller.
One of Melbourne Performance Centre’s six Evo II-spec Audis missed the session.
An accident for Theo Koundouris during the earlier 40-minute Bronze session ruled the #47 out of Practice 4.
Koundouris made heavy contact at Reid Park, leaving the car with damage to its right-rear corner.
The #888 Triple Eight Mercedes-AMG also suffered a crash on Friday.
The #888 missed a large part of Practice 4 after Prince Jefri Ibrahim crashed at Griffins Bend.
Triple Eight managed to return the car to the session, with Broc Feeney lapping to ninth.
Cars will return to the track for Practice 5 at 8:05am local time on Saturday.
Saturday’s running will be headlined by two-part qualifying and the Pirelli Shootout.