Anja Jul Andersen scored eight goals as Denmark beat the inexperienced United States, 29-19.
All eight women's teams played on the first day of preliminaries, including Hungary, who got 11 goals from Eszter Matefi in a 29-19 victory over China. Norway beat Angola, 30-18.
"America played very well, but they still need some tactics," Denmark goalie Susanne Lauritsen said. "It's like American football tradition. We're not good at that in Europe. There is no tradition."