SESTRIERE, Italy - Julia Mancuso never knew what this felt like. To win a major race, or even to lead after the first run.

And yet the 21-year-old Californian knew exactly what this felt like. To launch herself into the kind of whitewash of dense fog and driving snow that enveloped the Olympic giant slalom course Friday.

So she shut out the unknown and focused on the familiar. Her reward: A gold medal, the first for U.S. women in Alpine skiing since 1998 and their first medal of any color at these games.

“Just another day on a stormy race course,” said Mancuso, who’s seen plenty of such afternoons back home near Lake Tahoe. “That sort of helped me take the pressure.”

Just another day?

Mancuso awoke without a breakthrough victory in the Olympics, World Championships or World Cup. She ranks only ninth in the World Cup giant slalom standings. Extra incentive: The U.S. women’s Alpine team entered its final race here without any finishes better than sixth — forget about earning a medal — at either of the past two Olympics.

“She knew today she had to do it,” her father, Ciro, said.

Entering the second run, Mancuso was clinging to a mere 0.18-second lead over Sweden’s Anja Paerson, who won the slalom here and was bidding for a record-tying sixth Olympic medal.

The conditions were challenging enough that the race was shortened, the floodlights were on for the opening midmorning run and course workers kept repainting the course’s blue outlines. Skier after skier ahead of Mancusco barely managed to negotiate unusually tricky turns on fresh flakes.

“I was ready to give my best and not hold back just because I couldn’t see,” said Mancuso, who dispensed with the costume jewelry tiara she sported in an earlier race in favor of a white helmet that blended with the snowfall.

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Somehow, some way, she struck the proper balance between going right at the gates and using enough caution to stay upright. She had the second-fastest closing run for a cumulative time of 2 minutes, 9.19 seconds — 0.67 ahead of Tanja Poutiainen, whose silver was the first ever Alpine Olympic medal for Finland. Anna Ottosson of Sweden was 1.14 behind for the bronze.

Paerson wound up sixth, and her father and coach, Anders, said afterward she might need knee surgery after the World Cup season. At least Paerson raced. Croatia’s Janica Kostelic, the defending champion, and U.S. star Lindsey Kildow missed the race because of illness or injury.

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Even if the field was diluted, Mancuso had to come through.

“You’re not going to win at this level, in these conditions,” said U.S. Ski and Snowboard Association president Bill Marolt, “unless you’re mentally really tough.”

Clearly Mancuso is.