Yun Sung-bin got South Korea's first win in skeleton World Cup history to end a perfect season for six-time defending champion Martins Dukurs.
Yun was third after the first run led by Latvia's Dukurs, then raced down the Olympic course again hitting almost 134 kph for victory by .07 seconds, overall.
Dukurs tied his older brother Tomass for second place, after winning six straight World Cup events to start the season.
Canada's top man was Barrett Martineaum, who finished 15th, 2.65 seconds behind. Dave Greszczyszyn was 18th.
The 21-year-old Yun was on the podium for four of those Dukurs wins but finally rose to the top step and strengthened his hold on a distant second place in the standings.
The St. Moritz race doubled as the European Championships and the Dukurs brothers shared gold. Nikita Tregybov of Russia took bronze.
In the women's event, Janine Flock of Austria got her first World Cup victory of the season to be crowned European champion.
Flock, who won on the same track one year ago, was .08 faster over two runs than Tina Hermann of Germany, the dominant racer this season who leads the standings.
Bronze medallist Marina Gilardoni of Switzerland was a further .01 behind. Gilardoni touched 131.6 kph in posting the fastest time of the second run.
Canadian Jane Channell finished ninth, .98 behind Flock. Elisabeth Vathje finished 11th.