Scott McLaughlin set the pace in Practice 2 for the BetEasy Darwin Triple Crown over team-mate Fabian Coulthard, as Shell V-Power Racing finished Friday first and second.
McLaughlin recorded a 1:06.0800s at Hidden Valley to end up 0.1414 seconds clear of Coulthard, also his closest rival in the championship.
They were followed by Jamie Whincup and Chaz Mostert, while Shane van Gisbergen was 11th and will tackle the first phase of knockout ARMOR ALL Qualifying on Saturday.
David Reynolds beat Mostert's Practice 1 benchmark by a tenth on his first flying lap, with a 1:06.6423s to sit just ahead of McLaughlin after the opening runs.
McLaughlin reversed that order at the top with a 1:06.4158s set with eight of the 30 minutes remaining.
Amid a flurry of late improvements, Whincup went fastest briefly, before McLaughlin went quicker again on a 1:06.0800s that was not beaten.
“There’s so much more pressure now in practice. It’s tough, you’ve got to really be focused for the laps,” McLaughlin said, noting the knockout Qualifying format.
“It’s always good to get one in, Fabs is up there for the team too, which is great.”
Coulthard and the Red Bull Holden Team's Whincup were both within two tenths of McLaughlin in second and third, while Mostert was 0.2456s adrift.
“We’re on track. The car is reasonable, not the quickest, but we’re the best of the rest and we’re chipping away,” Whincup said.
“[Engineer David] Cauchi and the engineers did a great job of the balance, that’s all you can do, balance what you’ve got.
“We’re still lacking grip overall. It’s hot, the track slowly deteriorates... a little bit more grip would be nice, but how to do that I don’t know.”
Reynolds wound up fifth, from Lee Holdsworth, Anton De Pasquale, James Courtney, Cameron Waters and Mark Winterbottom.
Van Gisbergen occupied 10th and the last Q2 free pass when the chequered flag came out, but was bumped out by Waters' final effort.
Rookie Macauley Jones took 15th, one place ahead of the best of the Kelly Racing Nissans, Andre Heimgartner.
Practice 3 on Saturday morning at 10:50am local time is followed by knockout ARMOR ALL Qualifying and a 42-lap race.