Pietila Holmner -- victorious in the slalom at Aspen in November -- comfortably vanquished Tina Maze of Slovenia in the women's final.
”Both leading and being behind can be unbelievably stressful, but in my I found myself, I just had to give it my all. And that was enough,” Pietilä Holmner told the TT news agency following the race.
Austria's Elisabeth Gorgl completed the podium in the women's event, while Croatia’s Ivica Kostelic beat Frenchman Julien Lizeroux in the men's final.
An event reserved for the top 16 Alpine skiers in the World Cup, the parallel slalom gave a clear advantage to the most technical skiers in the field.
Furthermore, the one-on-one duals on a small hill adjacent to Munich's Olympic Park only count towards the overall World Cup standings and had little impact on the World Cup hierarchy.
The fan-friendly contest, which featured music and light shows, contained a number of surprises.
Germany's Maria Riesch, the women's World Cup leader, unexpectedly fell at the first hurdle against Italy's Daniela Merighetti, who ultimately finished fourth.
Riesch's nearest rival, the American Lindsey Vonn, fared little better.
Vonn was eliminated in the quarter-finals, but did manage to move to within 106 points of Riesch in the overall standings.
Vonn's compatriot Ted Ligety, who dominated the first three giant slaloms of the winter, was beaten by Lizeroux on his first attempt.
Kostelic dominated his final against Lizeroux, who lost his grip on the contest in the final stages, with America's Bode Miller taking third place.