Broc Feeney used an aggressive undercut strategy to seal a second career Supercars win at Albert Park.
The race started under unique circumstances, the safety car leading the field for a lap before releasing the cars in single file.
That was part of mitigation measures taken by Supercars after two separate engine fires on Friday and Saturday.
Polesitter Feeney initially led, although starting on Dunlop’s hard compound meant he would always be easy prey.
He was quickly swamped by the two supersoft-clad Mostert and Will Brown, who dived to either side of the Red Bull Camaro on the first green flag lap.
Feeney and the rest of the tough runners, including Andre Heimgartner and Brodie Kostecki, all dove into the pits at the end of that green flag lap to take on the super soft tires.
With that, Mostert Brown led until lap 4 when the Erebus driver played for the lead outside Turn 13.
However, it proved unsuccessful, Brown lost control of his Camaro on the exit of the corner and spun into the wall.
Mostert then led Bryce Fullwood until lap 8 when a significantly faster Fullwood took the lead at Turn 1.
With Fullwood pulling away, things got worse for Mostert, who was swamped by Will Davison, Shane van Gisbergen and Jack Le Brocq on the next lap.
What later turned out to be a blown tire caused him to fall back even further before stopping.
Simultaneously, the early stoppers emerged, with Feeney, Heimgartner and Kostecki coming within one stop of the lead despite being on the road towards the back end of the top 10.
When the top eight all gave up their mandatory service on the penultimate lap, the early stop strategy paid off.
Feeney shot to the top ahead of Heimgartner and Kostecki while Fullwood dropped to fourth ahead of van Gisbergen.
Fullwood’s day then deteriorated during the stops, contact with Mark Winterbottom in the lane resulting in a 15 second penalty.
In the last lap there were no changes at the top, Feeney achieved his second career win with a lead of almost a second over Heimgartner.
“When I got through the first lap, I was almost faster than [Mostert and Brown] down my spine I thought, ‘That’s good,'” Feeney said.
“I let Chaz and Will go and tried to get behind them.
“Fresh air was great. This morning it was a coin toss what we would do, but we certainly made the right strategy.
“What a way to win, Grand Prix Sunday. I’ve dreamed of this for a long time.”
Third place for an in-form Kostecki meant he walked away with the Larry Perkins Trophy.
The Erebus driver also took the lead in the series from Mostert, who was struggling to finish 14th thanks to this tire issue.
Fullwood crossed the line in fourth but was demoted to 18th thanks to his penalty.
That moved van Gisbergen up to fourth ahead of Le Brocq, Davison, Macauley Jones, David Reynolds, Todd Hazelwood and Cam Waters.
The 2023 Supercars season continues with the Perth SuperSprint on the last weekend in April.