A two-part qualifying session was used to set the order for a Top 10 Shootout later this afternoon and lock in starting positions 11 through 25.
Waters paced Q2 with a 1:29.2090s best to be 0.0928s clear of Feeney; the pair which shared the front-row for Races 1 and 2 again setting the standard.
When the chequered flag fell the remainder of the 10 read Brodie Kostecki, Chaz Mostert, Matt Payne, James Golding, Will Davison, David Reynolds, Thomas Randle and Ryan Wood.
Brown and Erebus driver Jack Le Brocq sat 17th and 18th but were the only drivers who returned for a second Q2 run in the dying seconds.
Le Brocq shot to fourth and Brown scraped into 10th, bumping Mustang duo Randle and Wood from the Shootout.
Asked if he’d made an error on his first run, Brown explained: “Not really a little error, just a lot of understeer crept into the car.
“That first run (Q1) I had a little bit, but I was quite fast, we were second and I was happy to leave the car, but on that first set of greens in Q2 I just pushed really bad at Turn 2 and lost a lot of time.
“I knew we’d have to come in and fit the used set of tyres and thought it would be hard to get through, so to get in the top 10 on that was awesome.
Q1 had also been a nervous one for Brown. On that occasion the majority did two runs while Brown did just one, rocketing from 24th to the top with the chequered flag flying.
De Pasquale subsequently bumped Brown to second at the end of the Q1 session, which trimmed the 25-car field back to 18, but the Team 18 driver only managed 16th when it mattered in Q2.
The Top 10 Shootout will take place at 1:05pm local time.
Results: Repco Supercars Championship Sydney 500, Qualifying for Race 3
| Pos | Num | Driver | Time | Diff | Gap |
| 1 | 6 | Cameron Waters | 1:29.2090 | ||
| 2 | 88 | Broc Feeney | 1:29.3018 | 0.0928 | 0.0928 |
| 3 | 38 | Brodie Kostecki | 1:29.3756 | 0.1666 | 0.0738 |
| 4 | 9 | Jack Le Brocq | 1:29.3824 | 0.1734 | 0.0068 |
| 5 | 25 | Chaz Mostert | 1:29.3880 | 0.1790 | 0.0056 |
| 6 | 19 | Matthew Payne | 1:29.4906 | 0.2816 | 0.1026 |
| 7 | 31 | James Golding | 1:29.4910 | 0.2820 | 0.0004 |
| 8 | 17 | Will Davison | 1:29.5240 | 0.3150 | 0.0330 |
| 9 | 20 | David Reynolds | 1:29.5258 | 0.3168 | 0.0018 |
| 10 | 1 | William Brown | 1:29.5264 | 0.3174 | 0.0006 |
| 11 | 55 | Thomas Randle | 1:29.5282 | 0.3192 | 0.0018 |
| 12 | 2 | Ryan Wood | 1:29.5944 | 0.3854 | 0.0662 |
| 13 | 26 | Kai Allen | 1:29.6161 | 0.4071 | 0.0217 |
| 14 | 4 | Cameron Hill | 1:29.6168 | 0.4078 | 0.0007 |
| 15 | 14 | Bryce Fullwood | 1:29.6233 | 0.4143 | 0.0065 |
| 16 | 18 | Anton De Pasquale | 1:29.6399 | 0.4309 | 0.0166 |
| 17 | 10 | Nick Percat | 1:29.6966 | 0.4876 | 0.0567 |
| 18 | 8 | Andre Heimgartner | 1:29.7273 | 0.5183 | 0.0307 |
| Q1 | |||||
| 19 | 12 | Jaxon Evans | 1:29.9824 | 0.7734 | 0.2551 |
| 20 | 7 | James Courtney | 1:30.0389 | 0.8299 | 0.0565 |
| 21 | 96 | Macauley Jones | 1:30.1070 | 0.898 | 0.0681 |
| 22 | 99 | Cooper Murray | 1:30.1571 | 0.9481 | 0.0501 |
| 23 | 62 | Richie Stanaway | 1:30.2019 | 0.9929 | 0.0448 |
| 24 | 3 | Aaron Love | 1:30.3248 | 1.1158 | 0.1229 |
| 25 | 35 | Cameron Crick | 1:30.7736 | 1.5646 | 0.4488 |
