The French skier won the giant slalom at Lenzerheide, the event in which she took gold at last year's world championships, to claim her first World Cup win since Maribor last January.
Worley, who missed the 2014 Sochi Games with a serious knee injury, led after the first run with one minute 5.33 seconds, and, although she was only seventh-fastest on her second, it was enough to pip Viktoria Rebensburg by seven hundredths of a second.
Meta Hrovat was third, the first time the 19-year-old Slovenian has finished on a World Cup podium.
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Shiffrin, fifth after the first run, dropped to seventh after the second and finished nearly two seconds behind Worley.
Tessa Worley, victorieuse du géant de Lenzerheide (Suisse) le 27 janvier 2018
Image credit: Getty Images
Shiffrin is widely expected to retain the Olympic slalom title she won in Sochi as well as having a shot at gold medals in the giant slalom and Super G.
Although the 22-year-old American has won 10 World Cup races this season and has more than twice as many points as her nearest contender in the overall standings, she has suffered a dip in form in the run-up to Pyeongchang.
She failed to finish her last two races before Saturday -- the Super G at Cortina and giant slalom at Kronplatz.
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