The Austrian star was 0.35 seconds faster than Andre Myhrer of Sweden, who wore bib No. 2 and got second use of a clean snow surface.
Henrik Kristoffersen of Norway was third, trailing 0.59 behind Hirscher who leads their duels in the season-long standings.
Hirscher is the six-time defending overall World Cup champion, and swept the giant slalom and slalom races at nearby Adelboden last weekend.
The home Swiss team quickly lost its best hope, when Alpine combined world champion Luca Aerni straddled the fifth gate.
Britain’s Dave Ryding also skied out and risks losing his place in the elite group of top-seven starters.