American Julia Mancuso claimed the gold medal in the women's giant slalom with a powerful run in a snowy Sestriere.
Mancuso shows her delight after clinching giant slalom gold
Leading after the first run, Mancuso stormed home in a combined time of two minutes 09.19 seconds.
Finland's Tanja Poutiainen claimed the silver medal in 2:09.86, ahead of Sweden's Anna Ottosson (2:10.33).
Slalom gold medallist Anja Paerson slipped from second after run one to sixth, while Briton Chemmy Alcott climbed from 32nd to 22nd overall.
"I can't believe it. I was freaking out at the start because the course was tough," said 21-year-old Mancuso. "I'm really happy. Today I had so much fun doing this race. I wasn't thinking of gold. I was thinking of the podium."
Austria's Nicole Hosp, a silver medal winner in the women's slalom, finished fourth.
Croatia's Janica Kostelic, the defending Olympic champion, did not race because of illness.
The 24-year-old, who captured three golds and a silver at the 2002 Olympics, defended her combined crown this time while taking silver in the Super-G.
Paerson, who claimed a first Olympic gold in the slalom on top of the bronzes she won in the downhill and the combined, would have joined Kostelic on a record six Olympic medals had she finished on the podium.
"I'm happy, this has been a good Olympics," said Paerson, for whom victory would have emulated compatriot Ingemar Stenmark's double gold in the technical events in 1980.
"It was always a tough fight with the snow. I really wanted to have medal today, but you can't have it all."
Mancuso, who won bronze medals in the giant slalom and super-G at last year's world championships, has had a hat-trick of top-three finishes on the World Cup circuit this year.
But she has yet to win a World Cup event and is ninth in the World Cup giant slalom standings.
"I was just ready for this win now," Mancuso said afterwards. "I don't know why.
"I was a little bit surprised at the finish. It took a while to sink in, but I guess everyone felt that way."
Mancuso's first ever Olympic medal will prove a welcome tonic for the USA.
Their Alpine team have failed miserably after setting out on a quest for at least eight medals.
Ted Ligety won the men's combined title last week but compatriots Bode Miller, Daron Rahlves and women's speed specialist Lindsey Kildow have disappointed.