Maze won her fourth straight GS race on Sunday to extend her overall World Cup lead — and more importantly create a bigger gap to Vonn, the defending champion who had another disappointing day and failed to finish.
Maze had a comfortable lead of 0.63 seconds over Frenchwoman Tessa Worley after her first run and the 29-year-old Slovenian then held off Austria's Kathrin Zettel in the second to win by 0.22. Worley was third, 0.40 back. Austria's Anna Fenninger finished fourth but was 1:16 behind Maze.
"This year I'm actually amazed by myself, how good I can do the races," Maze said. "For this I have to thank my team, that's working the whole summer and already for four now with me. They're getting me ready to be able to follow all the races that are coming."
The race was held despite heavy snowfall and the Stade Emile-Allais course was hard and bumpy, with poor visibility for the first run.
Maze, who was second overall behind Vonn last year by 578 points, let out a whoop of joy as she won. Vonn trails Maze by 385 points with more of the Slovenian's favoured technical events coming up in the Swedish resort of Are later this week.
"In sport it's always going up and down. Lindsey did a good job the last three years," Maze said. "For many races she was all the time at the top, so I knew that if I wanted to win the World Cup I needed to work as much as I can to be able to follow her."
Maze has improved every year over the four previous seasons — sixth, fourth, third, second — but felt she was still some way from challenging Vonn and former champion Maria Hoefl-Riesch of Germany.
"I knew I needed to win, win, win (races), not just one win," Maze said. "So, yes, this was pushing me the whole summer."
Meanwhile, Zettel lost some time at the top but was very quick down middle and bottom of the course. Worley did the opposite, pushing ahead of Zettel at first time split but then losing time in the bottom section.
"It was a tough race today, really tough with the light in the first run. I didn't find a lot of rhythm and did get a lot of speed (in the first run)," Zettel said. "So I tried to attack the second run and did it much better, so I'm happy about that."
After getting her 10th career podium — all in giant slalom — and first on home snow, the 23-year-old Worley said she "loved the tough conditions because I know I can do well if I can fight."
Vonn, however, was left looking dejected after losing her balance in the first run, lifting up her right knee slightly and then falling sideways to the left. The latest setback came after her crash in Friday's downhill and she dropped a place down to fourth overall as Zettel moved up to third.
"It's not the best period (for Vonn)," Maze said. "It's really hard to be at the top all the time."
Vonn stood for a few seconds with her head down and then lifted up one of her skis as if to inspect it.
"Hit a rock on my left ski in the GS and skied off course," Vonn, who spent time in a hospital with a stomach bug in November, said on her Facebook page. "(I am) struggling to find the energy I usually have...going to think hard over the next few days about my plan for the coming weeks and how to get strong again. Trying to stay positive. "
Maze has 799 points and a massive lead of 331 over Hoefl-Riesch, who finished a lowly 26th.
"I was already thinking about the overall for the last three years, every year I was trying to keep up with the best ones," Maze said. "This year I'm leading so it's working really good for me."
The way things are going, Vonn's deficit on Maze looks likely to get bigger before the end of the year.
"She's in a really high-pressure situation and Tina's skiing so well," said Julia Mancuso, Vonn's U.S. teammate. "She's just hanging in there and fighting. She's a great competitor so she'll never give up."
Having failed to gain any points on Maze when the super-G in Val d'Isere was cancelled on Saturday, Vonn now has two more technical events — a giant slalom and slalom — in Are, Sweden later this week.
Following Are, Vonn then has a slalom and giant slalom in Semmering, Austria, and will not get back to her favoured speed events until early January when there is a downhill and a super-G at St. Anton am Arlberg in Austria.
"We have a really tough rhythm with all the races to come. Tomorrow we are going to Are (Sweden)," Maze said. "It's really hard to keep up your shape and change from one place to another."
The U.S. team had something to cheer as Mancuso finished sixth — although she was 2:33 behind Maze, while the 17-year-old Mikaela Shiffrin improved in her second run to finish ninth.