The American ski star nearly skidded into safety nets rounding a corner halfway down the course and was off balance coming out of the turn Saturday.
Vonn righted herself and won the 13th World Cup race of her career at Lake Louise by over half a second.
"A lot of people make mistakes in a lot of races, but if you don't think you're going to win after a mistake then you're not," Vonn said. "I kept charging.
"I knew I could make up some time if I skied well on the bottom and thankfully my skis were fast and I had a good line and I was able to make it up."
The reigning Olympic and World Cup champion won the season-opening downhill Friday by over a second and a half.
It was another one-two finish for the U.S. team Saturday with Stacey Cook taking silver for a second straight day. Vonn's time was one minute 52.9 seconds. Despite her slip, she was still 0.52 seconds ahead of Cook in 1:53.42.
Marianne Kaufmann-Abderhalden of Switzerland was third in 1:53.52. Larisa Yurkiw of Owen Sound, Ont., was the lone Canadian in the race and she finished 47th.
Vonn races super-G on Sunday and can become the first woman to sweep all three races twice at Lake Louise. The 28-year-old from Burnsville, Minn., scored a Lake Louise hat trick in 2011. The only other woman to do so was Germany's Katja Seizinger in 1997.
"I did it last year and I'm going to do my best but super-G is a whole other ball game," Vonn said. "I really hope I can get another sweep, but I would be extremely happy to be on the podium."
Vonn drew on her previous experiences of overcoming misfortune on the Lake Louise course.
In 2009, Vonn crossed the finish line with blood dribbling from her mouth. Her knee connected with her chin during the race, yet Vonn still won the first of her two downhills that year.
In 2010, Vonn went down on her left hip entering a section of the course named Fall Away, but made an impressive recovery on the slope's face. She made up time on the bottom section and finished second to Germany's Maria Hoefl-Riesch.
Regaining her balance Saturday to win required strength and agility.
"I'm a little bit more tired today for sure, especially with that mistake," Vonn said. "It was definitely interesting today and an adventure. I've made mistakes here before. I haven't won with that big of a mistake before."
Vonn arrived in Lake Louise this year feeling drained because of a stomach ailment that hospitalized her Nov. 12 for two nights.
She also felt considerable pressure to win the women's races because she'd asked the world governing body of skiing to race the men's World Cup at Lake Louise. Vonn was denied by FIS, but hasn't given up on that dream.
Her best argument to race the men at Lake Louise is to continue winning by large margins.
"I've been racing here for so many years that there's definitely been a lot of interesting things that have gone in the races, but this weekend was very important for me to make sure I won at least one race and to come away with two wins is more than I hoped for being sick," she said.
"I felt like I had a lot of pressure coming into these races because I, of course, wanted to race the men. You make that kind of statement, you kind of have to back it up. I'm confident in the way I ski here. I know what to do and I think I proved that this weekend."
Cook watched Vonn's run on television monitors at the bottom of the course.
"I was like 'I don't have a chance' and then I saw her make a mistake. My heart stopped beating for a second," Cook said. "But she's so good. She's the only person who can stop and still win."
Cook was enjoying Lake Louise as much as her teammate, however, because the first two World Cup podiums of her career came at the mountain resort west of Calgary.
"I really kind of lifted a monkey off my back yesterday getting that first podium out of the way," the 28-year-old said. "I know I can compete with these girls. It's just been a long time coming to actually believe it and I think I'm starting to."
Vonn's victory Saturday ties her for second with Vreni Schneider of Switzerland all-time in World Cup victories at 55. Vonn is seven wins back of the 62 held by Annamarie Moser-Proell of Austria.
Yurkiw will be joined by Marie-Pier Prefontaine of Saint-Saveur, Que., and Marie-Michele Gagnon of Lac-Etchemin, Que., in Sunday's super-G.