Hirscher heads Wengen slalom after first run
Marcel Hirscher clears a gate during the first run of the Alpine Skiing World Cup Men's Slalom on January 19, 2014 in Wengen - by Fabrice Coffrini
The Austrian, chasing a 23rd World Cup career victory, clocked 51.22 seconds, with Sweden's Andre Myhrer in second at 0.23sec.
Germany's Felix Neureuther, the winner on this slope last season, was third at 0.64sec.
The soft snow on a rutted course took its toll of casualties, notably Japanese hope Naoki Yuasa, who was helped away by medical staff nursing a right knee injury after a heavy fall.
American Ted Ligety also had a disastrous run, missing a turn with the finish line in sight and eventually coming through a massive 7.71sec off Hirscher's pace, and was later disqualified for having missed a gate.
Croat veteran Ivica Kostelic, a four-time slalom winner in Wengen, also looked laboured, coming in at 5.38sec to miss the cut for the top 30 finishers who will race the second leg, slated for 1215 GMT.
For Ligety, who won Friday's super-combined, it was another dose of the bad luck he says has been dogging him this season, especially in the slalom.
"There wasn't much I could do there, I just got a little stuck on my ski," said Ligety, who won three golds at last year's world championships and is targeting three medals at next month's Sochi Olympics.
"The snow conditions were good, significantly better than in the combined that's for sure, but it's going to get rough this afternoon."