Hoefl-Riesch, the overall champion in 2011, was sent to hospital in nearby Chur with a suspected shoulder injury after crashing in the downhill which was won by Swiss Lara Gut.
The German's team later announced that she would not take part in the final races of the season.
Anna Fenninger was trailing Olympic super combined gold medallist Hoefl-Riesch by 29 points in the overall World Cup standings before the start but the Austrian finished sixth in the downhill and now leads by 11 points.
Hoefl-Riesch had already clinched the World Cup downhill title but was unable to receive her crystal globe at the medal ceremony after the day's race.
"It was a strange feeling to do the ceremony without Maria," Fenninger, who won the super-G title at the Sochi Olympics, said. "We don't like it to end this way.
"I hope she'll recover soon and return. I don't think about the overall. I ski my races and try to keep cool. I know that Maria could not be back and that Tina (Maze) needs to win the next three races to beat me but I don't want to think about it."
With Hoefl-Riesch out of the final races in Lenzerheide, in-form Fenninger has an ideal opportunity to clinch the overall World Cup for the first time.
She holds a solid 235-point lead over third-placed Gut who won the last downhill of the season in one minute 32.31 seconds.
Austria's Elisabeth Goergl was second, 0.05 behind and Swiss Fraenzi Aufdenblatten was third.
In the men's downhill, Olympic champion Matthias Mayer validated his gold medal with his maiden World Cup victory.
"It's a great way to end the winter," the 23-year-old Austrian, unexpectedly crowned in Sochi, said.
"To win today is something unique for me because it's my first World Cup victory. I achieved in a few months my goals for my whole career.
The demanding profile of the Swiss piste favoured technical skiers and allowed giant slalom Olympic and world champion Ted Ligety to clinch his first downhill podium.
The American was tied for second place with Olympic silver-medallist Christof Innerhofer of Italy, 0.11 seconds behind Mayer.
A rather disappointing fifth, 0.20 adrift, was Norway's Aksel Lund Svindal who collected 45 points and claimed back the overall World Cup lead on 1,091 points, 41 more than Austria's World Cup holder Marcel Hirscher.
"In terms of the overall title, it's almost too exciting right now. We're both at the same place right now and I have to say it's definitely 50-50," said the Norwegian, who already won the downhill crystal globe.
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- Anna Fenninger