The United States skier, twice an Olympic champion, missed out on the podium at this year's Beijing Winter Games but secured her fourth World Cup overall title in March and she started this season as she means to go on with a characteristically powerful performance.

Shiffrin's win means that, since 2015, every women’s World Cup race at this venue has been won either by her or Vlhová, the current Olympic slalom champion who finished third today, 0.20sec adrift of her US rival.

Anna Swenn-Larsson of Sweden was second, 0.16 back.

The slalom field goes again tomorrow.

It was Shiffrin’s 75th title, putting her seven short of compatriot Lindsay Vonn's women’s record, and 11 shy of Sweden's Ingemar Stenmark.

"It's the first race of the season and I'm feeling good with my skiing, my skis felt amazing," said Shiffrin.

"I have a different team this season and it was smooth, it paid off."

Shiffrin had been third after the first run but brought her trademark zest to the second.

"It was a nice feeling on the first run, I felt pretty good, but I was holding back a little bit," she said.

"On the second run I made adjustments and it felt like a really good pace and tempo."

Shiffrin, who finished runner-up to Vlhová in both of last year's slaloms in Levi, had trained at the venue for a fortnight before the race, the first time she has prepared in such a way.

"Last year I felt jetlagged, all week, I was awake from 1am to 7am every night, I didn’t eat well,” she said.

"This year I didn’t have the jetlag, I feel fit and strong, and it paid off."

Asked what she would be naming her fifth Lapland reindeer, the traditional prize at Levi, she replied: "I'll come up with the name later, or tomorrow.

"I never think about a name before I race because I don’t want to jinx it."

Swenn-Larsson produced her best finish in Levi, and having been plagued by injuries and COVID-19 setbacks over previous seasons she was overjoyed.

"It is the perfect start to the season,” she said.

"Tomorrow I will try to be a bit more aggressive in the first part of the ski."

Vlhová, who had won the previous four slaloms in Levi, paid the penalty for a below-average first run.

"It was difficult, and in some parts I could have been better," she said.

"But it was good fighting, and I’m looking forward to going again tomorrow.

"Finally we can kick off the season and enjoy it.

"I will try to do everything tomorrow to take a sixth [Levi race win]."

Meanwhile Shiffrin commented there are "five or six girls with a good chance tomorrow."

The International Ski and Snowboard Federation had to cancel seven out of its first eight scheduled Alpine Ski World Cup races due to unseasonably warm weather, with one men's event taking place.

But the storage of almost 60,000 cubic metres of snow on the Levi Black ski slope in the spring enabled the course to be finished in top condition.