The 26-year-old made her first World Cup podium one to remember, beating the likes of Italian Marta Bassino and American Mikaela Shiffrin, who was hoping to match Lindsey Vonn's record of 82 World Cup victories. 

Grenier was top in both runs, finishing far in front of Bassino in a time of 1min 55.01sec.

Bassino's two consistent runs got her the silver medal, finishing with a gap to the Canadian of 0.37sec.

Just 0.03 behind the Italian was Slovakian Petra Vlhová, who earned the bronze.

"I still can't believe it," said Grenier after the race.

"It's a dream come true, I've been wanting this for so long.

"I'm going to cry I'm so happy."

Federica Brignone, also from Italy, and Lara Gut-Behrami from Switzerland, completed the top five, far in front of the rest of the field.

Coralle Frasse Sombet of France was joint-sixth with Shiffrin, who is still seeking an 82nd victory.

A poor second run from the American dropped her out of contention for the podium.

Olympic champion Sara Hector from Sweden was ninth.

In the men's race in Abelboden, Switzerland's Marco Odermatt was victorious in his homeland, winning the men's giant slalom in a time of 2:30.68, 0.73sec in front of Norwegian Henrik Kristoffersen.

Loïc Meillard made it two Swiss skiers on the podium, finishing 1.66 behind Odermatt for bronze.

Manuel Feller of Austria and Žan Kranjec of Slovenia were in the top five too.

Norwegian Lucas Braathen and Justin Murisier of Switzerland, who were among the top contenders, skied out in the first round.

Shiffrin and Odermatt continue to lead the FIS Alpine Ski World Cup standings.