Alpine skiing: Shiffrin gives US Olympic boost with Bormio slalom win

American teenager Mikaela Shiffrin handed the US ski team a welcome pre-Olympics boost with an impressive victory in the World Cup women's slalom in Bormio on Sunday.

The 18-year-old reigning world slalom champion clocked a combined time of 2min 00.41sec to finish 0.13sec ahead of Sweden's Maria Pietilae-Holmner, with France's Nastasia Noens in third (+0.62sec).

It was Shiffrin's sixth career World Cup victory and came in an event rescheduled from Zagreb.

"It's always good to keep success going," the Vermont-based Shiffrin said after battling pouring rain that left the course rutted and bumpy.

"I'm used to skiing in this kind of conditions because in the East Coast it's like this a lot. I just kind of get tough and go."

Her victory followed news that teammate Lindsey Vonn's participation at the Winter Olympics in Sochi could be in jeopardy as she bids to overcome a recurring knee injury.

Shiffrin led by three-hundredths from Pietilae-Holmner after the first run.

She showed a wise head on the second run: only leading by 0.01sec at the middle split, she opened up on the bottom half to ink her name in as one of the big favourites for Sochi.

Tina Maze, last season's overall World Cup title winner, finished well down the field at 2.26sec.

Reigning Olympic slalom and super-combined champion Maria Hoefl-Riesch of Germany, the current overall World Cup leader, had a terrible lapse in concentration high up on the second course, a rut throwing her up and out of her run.

It was a timely victory for Shiffrin after she finished second last week in Lienz behind veteran Austrian rival Marlies Schild, who finished sixth on Sunday.

Shiffrin and the 32-year-old Schild have now shared honours in the season's four slaloms, the Austrian winning in Courchevel and Lienz and the American in the opening run in Levi and here.

Shiffrin, however, has a 62-point lead in the slalom standings, while Hoefl-Riesch remains atop the overall standings on 611pts, two ahead of Liechtenstein's Tina Weirather.