Shane van Gisbergen has admitted he "misread" the Perth finale en route to victory.
Van Gisbergen ran down James Courtney in the closing laps to secure his eighth win of 2022.
Courtney gained track position after an early stop, and led with six laps remaining.
It was then when van Gisbergen claimed the lead; however, the Kiwi thought Courtney wasn’t in the equation.
It came after van Gisbergen shadowed Race 11 winner Will Davison in the opening stint.
"I misread today’s last race a bit," the defending champion said.
"After eight laps, daylight was third, and Will and I were cruising along, not knowing that James had pitted.
"The team told me James was the leader, but I thought he still had to pit.
"So I stayed back and made sure I had clear air, and then they told me he had already pitted.
"I passed James at Turn 7 and then the Safety Car came out at Turn 3, so I was relieved to get that pass done."
Van Gisbergen’s weekend was spoiled by a run to 11th in Sunday’s first qualifying session.
Mark Winterbottom impeded van Gisbergen in Race 11 qualifying, and the latter was unable to improve.
Van Gisbergen and Winterbottom later exchanged texts in the aftermath of the incident.
In all, van Gisbergen was pleased with his weekend, and leaves with an extended points lead.
Prior to the weekend, van Gisbergen had never won a race at Wanneroo Raceway.
He won his first Perth race, and Holden's 600th race, on Saturday night.
"Apart from our incident with Winterbottom during qualifying this morning, it would have been a great weekend for us," he said.
"The first qualifying session was really frustrating, but in the second qualifying session, we showed what we could really do.
"Although it was an awesome weekend, we still have some weaknesses.
"My race starts haven’t been great… I keep getting shockers.
"Our pit stops maybe aren’t quick enough to put the pressure on some of the other guys.
"Normally, it’s not a very strong track for myself, so it’s good to get a couple of wins here."
Van Gisbergen will bring his championship lead to Winton in three weeks’ time.