Shiffrin edged Slovakia 75 / 100th and Swiss Wendy Holdener 83/100, the day after the giant's cancellation due to bad weather conditions.
After being beaten twice by Vlhova last week on the two slaloms of Levi (Finland), Shiffrin got her revenge thanks to the best time of the second round.
"It was a big fight," she said soberly at the microphone of the International Ski Federation (FIS), overcome with emotion.
She remains undefeated in slalom in the Vermont resort (northeast), where she has won all five races between tight stakes since 2016.
This is the second victory of the winter for Shiffrin, after the opening giant of Sölden (Austria) at the end of October, the 71st of his career on the world circuit at just 26 years old.
Only Swedish Ingemar Stenmark (86) and American Lindsey Vonn (82) did better.
Three-time winner of the Big Globe (from 2017 to 2019), the American takes the lead in the general classification at Vlhova, which she is 20 points ahead of.
The French Nastasia Noens took 19th place in the slalom.
© 2021 AFP