Van Gisbergen passed Kostecki at turn 6 on the second-last lap after making contact with the back of the Coca-Cola Camaro on the way into the corner.
The move came shortly after Kostecki had been shown a bad sportsmanship flag for his robust defence against a faster van Gisbergen.
The matter was heard by Motorsport Australia stewards at Wanneroo this morning, the outcome of which was that the protest was dismissed.
That means van Gisbergen retains his race 1 victory.
