Down 2-0 in the final period, the Canadians rallied to force overtime, and then won it on Marie-Philip Poulin's power play goal 8:10 into the extra period. It marked the fourth time the two North American powers have met for the gold. The U.S. won only the sport's inaugural Olympic title in 1998.
Elsewhere, it was a day of firsts.
France swept the podium in the men's skicross, claiming all three medals in a Winter Games event for the first time; Adelina Sotnikova gave Russia its first Olympic gold in women's figure skating; Canada won its first gold medal in women's curling; and Maddie Bowman of the US won gold in the debut of women's halfpipe skiing.
Also, perennial Winter Games power Norway won the Nordic combined team competition - and its games-leading 10th gold medal.
On Day 14 of the Sochi Olympics, a Ukrainian skier withdrew from competitions in response to the deaths of dozens of anti-government protesters in her country.
"I don't want to participate when in my country people die," Bogdana Matsotska told The Associated Press.
FIGURE SKATING: The 17-year-old Sotnikova's victory dropped defending champion Yuna Kim into second place. Julia Lipnitskaia, the Russian sensation with the weight of a nation on her 15-year-old shoulders, again fell during her routine and ended up fifth. Carolina Kostner of Italy took bronze. The Russians have won three figure skating gold medals at the Sochi Olympics: team, pairs and women's. Only the women's was a surprise.
ICE HOCKEY: Poulin also scored Canada's tying goal in the final minute of regulation. Brianne Jenner scored the other for Canada, which has won 20 straight in the Winter Games since the Nagano final in 1998. Meghan Duggan and Alex Carpenter scored for the U.S. Switzerland beat Sweden for the bronze medal.
FREESTYLE: The 20-year-old Bowman edged silver-medalist Marie Martinod of France in ski halfpipe, while Ayana Onozuka of Japan took the bronze. Bowman put together a pair of athletic runs that produced the two highest scores in the finals. In the men's skicross, Jean Frederic Chapuis won the gold to lead the French 1-2-3 finish. Arnaud Bovolenta won silver and Jonathan Midol captured bronze.
NORDIC COMBINED: Norway finished third in the ski jumping and had to start the 20-kilometer race behind. But cross-country ski specialist Mangus Moan made up the deficit on the first leg and Norway outdueled Germany and defending champion Austria in the relay. Germany, which had the lead after the ski jump, took silver and Austria got the bronze.
CURLING: Canada's 6-3 gold medal victory in women's Olympic curling came at the expense of Sweden, which had beaten the Canadians for the title in Vancouver four years ago. Britain won the bronze by beating Switzerland 6-5.
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