The Kiwi won the opening three heats across Friday and Saturday, entering the final with a comfortable lead over Fabian Coulthard in the weekend's points standings.
Van Gisbergen was under siege from the opening corners of the double-points Race 4, however, losing the lead to Coulthard part-way through the opening lap.
The unruly Tekno Holden slid further down the order as the laps progressed, eventually finishing 14th in the race and fifth for the weekend.
The 24-year-old later revealed that he'd been driving with a broken front anti-rollbar from the opening lap.
“Right from the start on the warm-up lap the car was really loose, it felt funny,” he told Speedcafe.com.
“I was trying to hold them off on the first lap thinking that the tyres would come up, but I had nothing.
“After that I was just trying to stay out of everyone's way really.
“Unfortunately they all hit me anyway so we went from a straight car to one with bent panels everywhere.
“It would have been nice to be on the podium to reward the guys but unfortunately it was not to be.”
The failure in the Race 4 also prevented the Tekno team from assessing set-up changes made for the finale.
“We had the fastest car for the first two races and tried something a bit different for the third,” he said.
“We weren't the fastest then but were able to keep it because we had the track position.
“We went back and tried another thing today which would have been nice to get a read on, but it was not to be.”