After The Bend SuperSprint, the top four teams in the standings will progress to the televised grand final at the Supercheap Auto Bathurst 1000, with $20,000 on the line.
The final two final places are currently occupied Kelly Racing's Plus Fitness entry of Andre Heimgartner and Tickford's Bottle-O effort for Lee Holdsworth.
Fifth in the order was BJR's other entry of Nick Percat, the big mover at Phillip Island.
The 7-Eleven Commodore was quickest through pitlane with a time of 48.4844 seconds to gain three places.
Second and third on Saturday were Mobil 1 MEGA Racing's Scott Pye and Whincup's team-mate Shane van Gisbergen.
Penrite Racing took fourth and fifth with its David Reynolds and Anton De Pasquale Commodores, aiding the former's move from 12th to fourth in the race.
Occupying the top three places in the points score, the crews of Slade, Mostert and Heimgartner were seventh, eighth and ninth fastest.
Slade's #14 is the only entry that has been in the top 10 in each of the four points-scoring races.
There was more misery for Shell V-Power Racing, the winner of the PIRTEK Pit Stop Challenge in 2017 and '18, at Phillip Island.
Both of its Mustangs were excluded from the PPSC points for breaching pitstop requirement that the line-locker be deployed while a car is raised.