Teenager Henrik Kristoffersen of Norway was third, trailing 0.66 behind Hirscher's combined two-run time of 1 minute, 49.75 seconds.
Hirscher won this race for the past two years en route to taking the giant crystal globe as the world's best Alpine skier.
"It's very wonderful here," Hirscher said of the historic venue, which has been featured since the World Cup started in 1967. "It's kind of a special race and it's working pretty well for me."
Felix Neureuther of Germany lost his unbeaten record in 2014 by straddling a gate when poised to challenge Hirscher's time.
With 100 race points for victory, Hirscher now leads Aksel Lund Svindal of Norway by 23 points in the overall standings. Svindal is a speed specialist who skips slalom races.
Park City's Ted Ligety retained a distant third place overall despite skiing out in the second run.
Bode Miller placed outside the top-30 in the morning Sunday, failing to qualify for a second run.
The American veteran, who won this race in 2002, lost his race line and speed at the top of the final pitch.
David Chodounsky of the U.S. was eighth, 1.70 behind Hirscher, to follow his 10th place here one year ago.
The host Switzerland team offered little for an enthusiastic crowd of 12,000 spectators on a sunny day with temperatures rising above 43 F. Only Markus Vogel advanced to the second run and placed 17th.
"The crowd is one of the most fair on the World Cup tour," said Hirscher, whose next race is next Sunday in slalom at nearby Wengen.
The three-race Wengen meeting includes the Lauberhorn downhill Saturday that is the traditional highlight of the Swiss sporting year.