The 23-year-old Austrian, winner of a super-G in Garmisch-Partenkirchen a week ago, triumphed again with a combined time of two minutes 29.39 seconds.
"It's pretty exciting to win again today, a week only after that Super-G victory in Garmisch-Partenkirchen," Fenninger told reporters.
"It's a good feeling to be able to switch so well from one speciality to the other and from hard to softer snow.
"It gives me a lot of confidence for the finals next week in Switzerland and also for the coming seasons. I know that I still have more in me," she said.
Fastest in the morning leg, the former super-combined world champion left World Cup leader Tina Maze 0.44 seconds adrift, but the Slovenian added another record to her haul by earning her eighth podium place in succession in the discipline.
Maze is now on a record 2,154 points in the overall World Cup standings and will be aiming at the formidable 2,500-point barrier in the World Cup finals in Lenzerheide, Switzerland, next week.
"This season is really amazing, I'm so pleased by my performances, I'm skiing fast even when I'm tired as now," said Maze who made sure of the overall title last month and is in a position to win crystal globes in every discipline this season.
"I'm very proud of my great results and the records I have set this winter. Yet it's not over, and I'm looking forward to another exciting day tomorrow in the slalom.
"In fact I won't take a break now as I'll train some slalom later on this afternoon," she added.
German Olympic champion Viktoria Rebensburg was third in Saturday's race, 0.96 behind.
Finn Tanja Poutiainen, a former Olympic silver medallist, pulled out after hurting her knee in the morning run. Doctors suspected torn cruciate ligaments and Poutiainen will miss the Lenzerheide finals.
- Sports & Recreation