'Invigorated' Shiffrin takes World Cup tally to 97
The US ski great was placed second after the first run, trailing Anna Swenn-Larsson by 0.11sec.
But after Swenn-Larsson failed to nail her second run Shiffrin topped the podium by 0.54s from Norway's Mina Fuerst Holtmann, who was placed only eighth at the midway point.
Swenn-Larsson had to settle for third at 0.63s.
After landing her 60th World Cup slalom, Shiffrin, who turned 29 this week, was all smiles as she collected her favourite discipline's crystal globe trophy.
Shiffrin arrived at the World Cup finals in Austria intent on ending a season marred by injury on a high note.
The Colorado-born skier had returned from six weeks on the sidelines to win the slalom in Are last weekend and, with it, the discipline's title for the eighth time.
She is out of the running for the overall title which looks destined to go to Lara Gut-Behrami, who sat out Saturday's slalom.
Gut-Behrami is also targeting the giant slalom, super-G and downhill titles and if successful she will join Shiffrin, Lindsey Vonn and Tina Maze as the only women in history to secure four titles in a single season.
Shiffrin meanwhile was just happy to be doing what she does best.
"These days make me feel so invigorated, so alive. There's no pressure, it's just a privilege for me."
Still not fully recovered from her fall in Italy she is opting out of Sunday's giant slalom and next week's speed events.