While three Ford Mustang drivers, Cam Waters, David Reynolds and Thomas Randle fought for the win in the penultimate race of the year Kostecki, who started from pole position in his Erebus Motorsport Chevrolet Camaro, drove to a conservative sixth place, to assure himself of the title with Sunday’s race still to run.
The battle for the drivers’ title lasted less than 20 seconds, when Shane van Gisbergen’s Triple Eight Chevrolet got caught up in an opening lap clash between Will Brown and Anton De Pasquale.
Erebus driver Brown had been fed into the outside wall in a typically chaotic first run through Turn 4 and, as his Camaro rebounded back onto the track, Waters was fortunate to avoid any contact. But this left van Gisbergen completely blind to the danger and the ensuing contact left him with race-ending front suspension damage.
Brown, who will replace van Gisbergen at Triple Eight next season, described the moment as "difficult" but dismissed any wrongdoing from De Pasquale.
Waters seized the lead from Reynolds mid-race and built a small gap to take his third win of the season by 0.67 seconds.
After starting from pole, Kostecki finished sixth, with this enough to earn the title of provisional champion.
“It has not really sunk in yet," he said. "It’s been a whirlwind of a year, we have worked so hard to do what we have done this year.
Source: Autosport