So this is what it has come to, Vonn thought to herself. After several days of weather postponements, after a week of speculation about an injured right shin, after a year’s buildup to her quest for a medal, it would come down to one bold charge after an old familiar foe.

Image A number of skiers crashed, including, from top, Dominique Gisin of Switzerland, Anja Paerson of Sweden, center, and Edith Miklos of Romania. Credit... From top, Sandra Behne/Bongarts; Chang W. Lee/The New York Times; Stephan Jansen/European Pressphoto Agency

“One all-out run,” Vonn would later say, “with nothing left behind.”

In one of the most stirring descents in Olympic downhill skiing history, Vonn ignored the pain in her injured shin, chased down Mancuso and caught up to nearly a lifetime of expectations to become the first American woman to win an Olympic downhill gold medal. With an aggressive style and stance she held throughout her run  jaw, hands, knees and hips always angling forward for more speed  Vonn’s time of 1 minute 44.19 seconds on the bumpy, treacherous Whistler race course was 0.56 of a second ahead of Mancuso. Elisabeth Görgl of Austria won the bronze medal.

“It was a fight all the way down but I told myself to keep pushing regardless of the consequences,” said Vonn, who remains a favorite to win additional gold medals. “I had to go for it every second.”

While Mancuso’s thrilling run seemed smooth, elegant and efficient, Vonn’s seemed tinged with elements of force and desperation. The bruised shin sustained more than two weeks ago was painful, she said, but pain-killers and adrenaline masked the debilitating effects. From the start, Vonn built her lead over Mancuso, increasing it at nearly every timed interval down the race course. Still, she had one nearly disastrous bobble about two-thirds of the way down at the sharp right turn known as Frog Bank, and then, she almost lost it all 10 seconds from the end.