But she rallied in the second run to win her first world championship title.

A second comeback on a big stage seemed like a reasonable expectation Friday. And Shiffrin skied considerably better and more aggressively in her second run, turning in the third best time of the field.

But it was not her usual stellar performance, especially because Shiffrin has often defeated her competitors by a second or more in each run.

“Instead of focusing on the good skiing that I know I can do, I was conservative,” Shiffrin said afterward. “I was almost trying to do something special, and I don’t need to do something special. I just need to ski like myself, and I’ll be fine.”

Shiffrin, renowned for needing at least nine hours of sleep a day, said she had gone to bed two hours after her usual bedtime Thursday because she had attended the medal ceremony for the giant slalom.

Shiffrin’s mother, Eileen, who is also one of her coaches, said she believed fatigue had contributed substantially to her daughter’s atypical skiing. She noted that because high winds had postponed three races, the Alpine schedule had been compressed. The original plan was for a day of rest between the giant slalom and the slalom.