Vonn skied flawlessly to finish in 1 minute, 2.71 seconds, edging overall points leader Tina Maze of Slovenia by 0.37 seconds and her U.S. teammate Mancuso by 1.01.
The race course at the famed Swiss venue had to be shortened Saturday due to stiff winds; however snow conditions were good and there was some sunshine during the early runs.
The victory was nice rebound for Vonn, who skied out during Friday's super combined and slipped to fourth place in the overall women's World Cup standings.
"Today I came out charging because I knew that it was gong to be really difficult to win," Vonn said. "The other girls – Tina, Julia and Maria (Hofel-Riesch of Germany) -- are skiing so well. It has been a tight field in super G."
At the end of the day, Vonn was back on top in the super G standings followed by Mancuso and Maze. She was in third place in the overall standings behind Maze and Hofel-Riesch.
Maze's second place gave her a second trip to the podium in as many days. She won Friday's super combined.