Led by her young American rival in the morning run, the Slovenian overall runaway leader fought back in the afternoon to snatch her 10th victory of the World Cup season, her second in a slalom.
In a combined time of one minute and 52.85 seconds, Maze beat Swiss hopeful Wendy Holdener by 0.25 seconds while Shiffrin settled for third, 0.75 adrift.
"This victory is huge for me, and also somehow unexpected as I feel so tired now, I don't know how I'm doing it, where I find the energy to keep fighting and pushing myself ahead," an exhausted yet smiling Maze told reporters.
With 2,254 points, the utterly dominant Maze again increased the all-time points record in the overall World Cup and totals more than twice the score of nearest rival Maria Hoefl-Riesch of Germany, who is on 1,065 points.
The Slovenian, who beat Hermann Maier's previous record total of 2,000 points last weekend, also improved on one of the Austrian's other record statistics by earning her 22nd podium of the season.
In the slalom World Cup standings, she now leads second-placed Shiffrin by seven points with only one race left at the Lenzerheide finals next week.
Maze remains in contention to win all four discipline World Cups on top of the overall big globe.
"It's pretty crazy now to be fighting for three more globes next week in Lenzerheide. I like slalom a lot but it's such a tough speciality that requires intense training," she said.
"I'll do my best to remain focused next week in Switzerland, but it'll for sure be tough as Mikaela is such a great skier."
While the Slovenian now has a possibly once-in-a-lifetime opportunity to make history in Lenzerheide, she is feeling the strain of a long season.
"I really feel tired now, it's so hard to ski in all disciplines and fight each time for victory. The rhythm of racing is incredibly intense," she said.
"I'm looking forward to the end of the season now. I can't think about the fact that I'll be skiing again tomorrow in Lenzerheide where we have a downhill training run."