Cheered on by a throng of supporters who had made the trip from her native Slovakia, Vlhova clocked 51.30 seconds in the tightly gated opening run before following up with 56.32 seconds in the second.
"It was tough," laughed Vlhova who revealed in her post-race interview that the fog had made visibility so poor in the first run that she had had to clean her goggles "halfway down".
Vlhova put half a second on Lena Duerr in the second run with the German finishing 0.72 seconds behind.
"Of course I knew it would be tough from the first gate to the finish," she said.
"I needed to be ready and I wanted to be ready. I skied well, I skied exactly how I wanted. I pushed as much as I could.
"When I crossed the finish line and saw the green light it was an explosion, because in front of many Slovak people, it’s something different to win. This year it was one of the toughest."
Leona Popovic was third after the first run but a mistake halfway down the second knocked the Croat out of contention and allowed the American AJ Hurt to claim her first World Cup podium.
The 23-year-old Californian, whose previous best in a World Cup slalom was 29th, was 16th fastest wearing bib 38 on the first run, over two seconds behind Vlhova.
But she then pulled out the fastest run second time around to finish 0.87 seconds behind the Slovakian.
"It feels amazing," said Hurt who admitted that the 'soft' snow on the suited her.
"It doesn’t really feel real right now, I don’t know what to say. I defiinitely didn’t really expect this."
Her teammate Shiffrin, however, endured a poor weekend.
Having finished only ninth in Saturday's giant slalom, her worst result in the discipline since November 2022, the five-time World Cup overall winner straddled a gate in the second sector and failed to finish, ruling her out of the second run.
It is the first time since the Beijing Winter Olympics in February 2022 that Shiffrin has gone out in her favourite event - 56 of her 93 World Cup victories have come in the discipline.
Vlhova is now just five points behind Shiffrin in the discipline standings but remains 207 behind the American in the overall, although she has jumped past Federica Brignone into second.
