"At the top I was actually a little bit nervous for the slalom and a little bit tired and I was like 'wake up your legs and go,'" Shiffrin said. "I made this little bit of a mistake on the fourth gate but then from there on out the timing was there and everything was moving forwards.
"It's part of who I am. It seems when things are more certain for me I get more nervous because I'm sure something's going to go wrong and there's more to lose in that sense. It's better for me to be nervous than not, I don't take things for granted usually and that ends up giving me wins like this."
Shiffrin extended her advantage in the overall standings to 300 points over Stuhec, who moved into second, two points ahead of Lara Gut, who is out for the rest of the season with injury.
"I'm really happy with today," Shiffrin said. "I'm happy with the progress I made from yesterday in the super-G portion and yeah of course happy with the slalom and excited to have a win and to take my overall lead into the U.S. races."
It was a third podium finish of the weekend for Stuhec, who was runner-up in the Alpine combined on Friday and won Saturday's super-G.
The result also saw her clinch the Alpine combined title — a first globe for the 26-year-old Slovenian.
"Amazing," Stuhec said. "I can't believe it really because it's something that I've always dreamed of and now that it's here it's just woah."
Stuhec can further cut the gap in the next two races in South Korea next week. Shiffrin is flying there on Sunday night to check out the venues for next year's Pyeongchang Olympic Games but will not contest the downhill or the super-G.
"I'm not going to race in the speed events," she said. "I'm going to try to see the speed hill, get on the tech venue a little bit and then go to the U.S.
"I've never been even close (to South Korea) so I am looking forward to seeing it, getting a feel for what it's like there and then I'm really excited to be going home."
Lindsey Vonn pulled out of the race last night after suffering from food poisoning and crashing on Saturday.
She also withdrew from Friday's combined race, along with Shiffrin and their American teammate Laurenne Ross, because of dangerous conditions on the course.
On Sunday morning Vonn wrote on Twitter: "Happy that my stomach feels better today. Have whiplash from my crash but otherwise ok. Now I need to regain some strength mentally."