The two title contenders started the 42-lapper side-by-side on the front row, Kostecki getting the best of the run to Turn 1 from the outside to sweep into the lead ahead of van Gisbergen and David Reynolds.
The leading trio then continued to run in that order across a fairly tame first stint, Kostecki's advantage sitting at around half a second.
That was until the end of lap 17 when van Gisbergen made his move, forcing Kostecki to the inside on the run to Turn 7. The Kiwi was then able to get a better run onto the front straight and ease past Kostecki into Turn 1.
Kostecki didn't give up, barging down he inside of van Gisbergen into Turn 7 on the very next lap – only to pit immediately after reclaiming the lead.
The squabble proved costly, though, with Reynolds – who had pitted on lap 17 – able to undercut Kostecki.
The pair then battled over what would become the effective lead until Kostecki was able to sneak back through at Turn 7.
Van Gisbergen, meanwhile, stayed out until lap 28 before resuming in what was effectively fourth behind Kostecki, Reynolds and James Courtney.
He did have better tyre condition, though, and within a handful of laps was able to clear both Courtney and Reynolds.
He then set about running down Kostecki's two-second lead, the battle coming to a head 13 laps from home.
Source: Autosport