Hirscher won the men's race held on the 200-foot-tall structure at the All-Russian Exhibition Center and Duerr scored her first World Cup victory in the women's event.
The format on the 650-foot course was head-to-head racing between two competitors until the field of 16 was whittled down to two finalists.
Hirscher's win extended his lead in the World Cup slalom and overall points standings. Andre Myhrer of Sweden took second place and Ivica Kostelic of Croatia placed third.
Duerr placed first in the women's competition ahead of Veronika Velez Zuzulova of Slovakia and American Mikaela Shiffrin, who widened her lead over Tina Maze of Slovenia in the slalom standings.