The Austrian, who arrived brimming with confidence after his night slalom win in Schladming, was nearly two seconds quicker than team-mate Manuel Feller.
American Ted Ligety competed the podium ahead of Norway's Henrik Kristoffersen.
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It was Hirscher's 55th World Cup win, moving him clear of the legendary Hermann Maier. Only Sweden's Ingemar Stenmark, with 86 wins, has been more successful.
Hirscher's dominance continues with 55th World Cup victory
In 15 races this season Hirscher has topped the podium on ten occasions, and only twice finished outside the medals. He's also won four of this season's giant slalom events.
Hirscher won Olympic slalom silver in Sochi four years ago but will be making a three-pronged assault on the podium in PyeongChang, starting with the giant slalom in Alpensia on February 18th.
Like his talent, Hirscher's retirement transcends the sport he dominated