The hour-long session got underway in the driest conditions seen since the third session on Friday morning.
There were no Hollywood times out the gate, though, as teams focussed on pitstop practice with driver and brake changes.
Boys set the first representative time with a 2m11.770s a few minutes in before Alex Davison took over with a 2m10.340s.
David Reynolds then dipped into the nines and then eights with a 2m08.562s right before he out-braked himself at The Chase and went off.
Dale Wood edged Reynolds' time at the 12-minute mark, only for Chaz Mostert to come out a few minutes later and set a 2m07.204s.
On 20 minutes the times shifted into the sixes when Will Davison, who had taken over the #17 DJR Ford from his brother, set a 2m06.804s.
Times continued to improve as the session neared the midway point, Shane van Gisbergen lapping in 2m06.406s as Anton De Pasquale dropped into second with a 2m06.667s.
The next improvement came from Mostert with a 2m06.165s right on half an hour, which remained the benchmark until the Shootout simulations started later in the session.
Those qualifying sims started with around 10 minutes to go when Davison jumped to the top with a 2m05.630s. At the same time DJR teammate Anton De Pasquale went second fastest with a 2m06.032s.
With two minutes to go van Gisbergen edged Davison with a 2m05.613s only for Mostert to go quicker again with a 2m05.510s.
That was as quick as anyone went thanks to a red flag that cut the session short in the final minute.
The culprit was Boys who swiped the wall at the metal grate and damaged the Brad Jones Racing Holden that the team stayed up late repairing after its qualifying run-in with van Gisbergen yesterday.
That left Mostert in first place ahead of van Gisbergen and Davison, who was on a lap when the red flag came out.
"It's never perfect, you know us race car drivers, we always like to keep tuning it," said Mostert. "But for me that session was the happiest I've been all weekend, wet, dry or whatever.
"We've been tuning the car and getting it a bit closer to the window we need for this weekend."
Provisional pole-sitter Cam Waters was fourth fastest ahead of Reynolds, De Pasquale and Brodie Kostecki.
Mark Winterbottom, Lee Holdsworth and Scott Pye rounded out the Top 10.
The Blanchard Racing Team Mustang, which will start tomorrow's raced from last place, didn't turn a single lap in the session.
That was thanks to an issue with the drop jacks that damaged the car as it went to leave the garage for its first run.
The first five rows of the grid will be determined by the Top 10 Shootout which kicks off at 5:05pm local time.
| Cla | Driver | Car | Laps | Time | Gap |
|---|---|---|---|---|---|
| 1 |
 Chaz Mostert  Fabian Coulthard
|
Holden Commodore ZB | 16 | 2'05.5105 | |
| 2 |
Shane van Gisbergen Garth Tander
|
Holden Commodore ZB | 16 | 2'05.6137 | 0.1032 |
| 3 |
Will Davison Alex Davison
|
Ford Mustang GT | 20 | 2'05.6305 | 0.1200 |
| 4 |
Cameron Waters James Moffat
|
Ford Mustang GT | 17 | 2'05.9821 | 0.4716 |
| 5 |
David Reynolds Matt Campbell
|
Ford Mustang GT | 17 | 2'06.0179 | 0.5074 |
| 6 |
Anton De Pasquale Tony D'Alberto
|
Ford Mustang GT | 22 | 2'06.0324 | 0.5219 |
| 7 |
Brodie Kostecki David Russell
|
Holden Commodore ZB | 18 | 2'06.2106 | 0.7001 |
| 8 |
Mark Winterbottom Michael Caruso
|
Holden Commodore ZB | 18 | 2'06.2106 | 0.7001 |
| 9 |
Lee Holdsworth Matthew Payne |
Ford Mustang GT | 20 | 2'06.3342 | 0.8237 |
| 10 |
Scott Pye Tyler Everingham |
Holden Commodore ZB | 19 | 2'06.3477 | 0.8372 |
| 11 |
Andre Heimgartner Dale Wood
|
Holden Commodore ZB | 24 | 2'06.3737 | 0.8632 |
| 12 |
James Courtney Zane Goddard
|
Ford Mustang GT | 20 | 2'06.5292 | 1.0187 |
| 13 |
Richie Stanaway Greg Murphy |
Holden Commodore ZB | 19 | 2'06.6016 | 1.0911 |
| 14 |
Will Brown Jack Perkins |
Holden Commodore ZB | 16 | 2'06.6643 | 1.1538 |
| 15 |
James Golding Dylan O'Keeffe |
Holden Commodore ZB | 22 | 2'06.8406 | 1.3301 |
| 16 |
Broc Feeney Jamie Whincup
|
Holden Commodore ZB | 20 | 2'06.8456 | 1.3351 |
| 17 |
Bryce Fullwood Dean Fiore
|
Holden Commodore ZB | 25 | 2'06.9435 | 1.4330 |
| 18 |
Todd Hazelwood Jayden Ojeda |
Holden Commodore ZB | 21 | 2'07.0420 | 1.5315 |
| 19 |
Nick Percat Warren Luff
|
Holden Commodore ZB | 17 | 2'07.0438 | 1.5333 |
| 20 |
Chris Pither Cameron Hill |
Holden Commodore ZB | 23 | 2'07.1388 | 1.6283 |
| 21 |
Macauley Jones Jordan Boys |
Holden Commodore ZB | 23 | 2'07.1641 | 1.6536 |
| 22 |
Thomas Randle Zak Best |
Ford Mustang GT | 25 | 2'07.5682 | 2.0577 |
| 23 |
Craig Lowndes Declan Fraser |
Holden Commodore ZB | 23 | 2'07.5797 | 2.0692 |
| 24 |
Jake Kostecki Kurt Kostecki
|
Ford Mustang GT | 24 | 2'07.7394 | 2.2289 |
| 25 |
Jack Smith Jaxon Evans
|
Holden Commodore ZB | 25 | 2'07.8430 | 2.3325 |
| 26 |
Matt Chahda Jaylyn Robotham |
Holden Commodore ZB | 21 | 2'08.1829 | 2.6724 |
| View full results | |||||
