Brown ran in second place for much of the 40-lap contest but jumped Mostert when they both pitted with 11 to go and eventually won by 1.5535s over the #25 Mobil 1 Optus Mustang.
Pole-sitter Broc Feeney finished 1.1770s further back in third in the #88 Red Bull Ampol Camaro after incurring an early penalty for feeding James Golding off the road.
The result means that Brown now leads the Repco Supercars Championship by nine points over team-mate Feeney, with Mostert 12 points further back in third, after those three drivers filled out the podium for the second day in a row.
Walkinshaw Andretti United’s Mostert had earned the outside front row berth and made a typically strong start which allowed him to take a clear lead to the first corner.
Golding (#31 PremiAir Nulon Camaro) slotted into second from the outside of the second row, ahead of Feeney.
When they arrived at The Chase for the first time, Feeney had a dive at Golding, both locked up, and both ran off, the latter deeper than the former.
Brown (#87 Camaro) nabbed second place as a result of the incident and Feeney resumed a net unchanged third, while Mostert was 1.5s up the road.
Golding had dropped all the way to eighth by the time the field sorted itself out again, behind Thomas Randle (#55 Castrol Mustang) in fourth, from David Reynolds (#20 Tradie Beer Camaro), Will Davison (#17 Shell V-Power Mustang), and Jack Le Brocq (#9 TFH Camaro) in seventh.
Anton De Pasquale (#11 Shell V-Power Mustang) ran ninth and Nick Percat (#10 Bendix Camaro) 10th, while Cameron Hill (#4 Tyrepower Camaro) was back in the pits with damage after a three-wide squeeze off the starting grid.
Stewards cleared that, but a five-second penalty for a driving infringement would be handed down to Feeney.
Both he and Brown needed only a handful of laps to catch back up to Mostert, and then Feeney asked if he was allowed to pass his team-mate.
The response on the radio was reportedly “No team orders” but they held station until both Mostert and Feeney pitted on Lap 11.
Brown pitted a lap later and resumed behind #25 but ahead of #88, which was ahead of the #55 Mustang of Randle, meaning the pre-pit stop top four was effectively unchanged despite Feeney having served the penalty while in the lane.
Once the first pit stop cycle was complete on Lap 17, Mostert led Brown by 5.8s after racking up some very quick lap times.
Feeney was just over a second back in third, from Randle, Reynolds, Matt Payne (#19 Penrite Mustang), Le Brocq, Golding, Percat, and Bryce Fullwood (#14 Middy’s Camaro).
Feeney had reduced Mostert’s lead to less than five seconds on Lap 21, and less than four on Lap 24, by which time Golding had kicked off the second pit stop cycle and thus completed his 60-litre fuel drop.
On Lap 28, Feeney peeled off from about 1.3s behind Brown, who had closed the gap to Mostert to just 2.4s.
The top two were into the lane on Lap 29 and there was a wheel nut drama for the WAU crew as they serviced the erstwhile leader.
They reportedly had to revert to a non-preferred wheel for the right-front and, while fuel covered the delay on the change – it turned out #25 had been relatively short-filled earlier – Triple Eight was able to drop and release Brown in front of Mostert.
When the cycle completed on Lap 30, Brown led Mostert by 0.9s, with Feeney about five seconds more behind in third, from Randle, Golding, Reynolds, Payne, Le Brocq, Davison, and Percat.
Despite the compromised tyre, Mostert reset the fastest lap on Lap 31 and was 0.6s behind Brown, but had drifted to 1.3s in arrears on Lap 35.
It was 1.8s as they started the final lap, before Brown clinched his first win for Triple Eight, 24 hours after a second place on his Supercars debut for the Banyo squad.
Mostert took second, from Feeney, Randle, Golding, Reynolds, Payne, Le Brocq, Percat, and Davison.
A total of 23 cars finished, including Aaron Love at three laps down after hitting the wall early on in the #3 CoolDrive Mustang, and Hill at nine laps down after repairs following his clash at the start, while Ryan Wood (#2 Mobil 1 Truck Assist Mustang) was the sole DNF.
Event 2 is the Melbourne SuperSprint, at the Formula 1 Rolex Australian Grand Prix, on March 21-24.
Results: Race 2, Thrifty Bathurst 500
Pos | Num | Team/Sponsor | Driver | Car | Laps | Split |
1 | 87 | Red Bull Ampol Racing | William Brown | Chev Camaro ZL1 | 40 | 1:27:19.1560 |
2 | 25 | Mobil 1 Optus Racing | Chaz Mostert | Ford Mustang GT | 40 | 1:27:20.7095 |
3 | 88 | Red Bull Ampol Racing | Broc Feeney | Chev Camaro ZL1 | 40 | 1:27:21.8865 |
4 | 55 | Monster Castrol Racing | Thomas Randle | Ford Mustang GT | 40 | 1:27:41.8394 |
5 | 31 | PremiAir Nulon Racing | James Golding | Chev Camaro ZL1 | 40 | 1:27:43.1967 |
6 | 20 | Tradie Beer Racing | David Reynolds | Chev Camaro ZL1 | 40 | 1:27:45.4270 |
7 | 19 | Penrite Racing | Matthew Payne | Ford Mustang GT | 40 | 1:27:46.5132 |
8 | 9 | Erebus Motorsport | Jack Le Brocq | Chev Camaro ZL1 | 40 | 1:27:54.0725 |
9 | 10 | Bendix Racing | Nick Percat | Chev Camaro ZL1 | 40 | 1:27:54.4049 |
10 | 17 | Shell V-Power Racing Team | Will Davison | Ford Mustang GT | 40 | 1:28:01.7721 |
11 | 26 | Penrite Racing | Richie Stanaway | Ford Mustang GT | 40 | 1:28:02.0404 |
12 | 14 | Middy’s Racing | Bryce Fullwood | Chev Camaro ZL1 | 40 | 1:28:02.7848 |
13 | 99 | Erebus Motorsport | Todd Hazelwood | Chev Camaro ZL1 | 40 | 1:28:04.5876 |
14 | 100 | DEWALT Racing | Mark Winterbottom | Chev Camaro ZL1 | 40 | 1:28:05.4416 |
15 | 11 | Shell V-Power Racing Team | Anton De Pasquale | Ford Mustang GT | 40 | 1:28:15.2679 |
16 | 6 | Monster Castrol Racing | Cameron Waters | Ford Mustang GT | 40 | 1:28:17.1718 |
17 | 23 | PremiAir Nulon Racing | Tim Slade | Chev Camaro ZL1 | 40 | 1:28:19.5809 |
18 | 8 | R&J Batteries Racing | Andre Heimgartner | Chev Camaro ZL1 | 40 | 1:28:19.7507 |
19 | 7 | Snowy River Racing | James Courtney | Ford Mustang GT | 40 | 1:28:30.9347 |
20 | 96 | Pizza Hut Racing | Macauley Jones | Chev Camaro ZL1 | 40 | 1:28:31.0824 |
21 | 12 | SCT Motorsport | Jaxon Evans | Chev Camaro ZL1 | 40 | 1:29:32.4747 |
22 | 3 | CoolDrive Racing | Aaron Love | Ford Mustang GT | 37 | 1:28:43.8675 |
23 | 4 | Tyrepower Racing | Cameron Hill | Chev Camaro ZL1 | 31 | 1:27:40.0321 |
NC | 2 | Mobil 1 Truck Assist Racing | Ryan Wood | Ford Mustang GT | 7 | 34:08.1428 |
Drivers’ championship
Pos | Driver | Pts |
1 | William Brown | 288 |
2 | Broc Feeney | 279 |
3 | Chaz Mostert | 267 |
4 | Richie Stanaway | 192 |
5 | David Reynolds | 192 |
6 | Nick Percat | 186 |
7 | Thomas Randle | 183 |
8 | Matthew Payne | 174 |
9 | Bryce Fullwood | 165 |
10 | James Golding | 162 |
11 | Jack Le Brocq | 156 |
12 | Cameron Hill | 147 |
13 | Todd Hazelwood | 138 |
14 | Andre Heimgartner | 135 |
15 | Will Davison | 135 |
16 | Mark Winterbottom | 132 |
17 | James Courtney | 108 |
18 | Tim Slade | 108 |
19 | Anton De Pasquale | 102 |
20 | Cameron Waters | 96 |
21 | Macauley Jones | 93 |
22 | Jaxon Evans | 87 |
23 | Aaron Love | 39 |
24 | Ryan Wood | 0 |
Teams’ championship
Pos | Num(s) | Team | Pts | |
1 | 87 | 88 | Triple Eight Race Engineering | 567 |
2 | 19 | 26 | Grove Racing | 366 |
3 | 4 | 10 | Matt Stone Racing | 333 |
4 | 20 | 100 | Team 18 | 324 |
5 | 8 | 14 | Brad Jones Racing | 300 |
6 | 9 | 99 | Erebus Motorsport | 294 |
7 | 6 | 55 | Tickford Racing | 279 |
8 | 23 | 31 | PremiAir Racing | 270 |
9 | 2 | 25 | Walkinshaw Andretti United | 267 |
10 | 11 | 17 | Dick Johnson Racing | 237 |
11 | 12 | 96 | Brad Jones Racing | 180 |
12 | 3 | 7 | Blanchard Racing Team | 147 |