Vonn, already the most successful woman in World Cup history, is now 10 victories behind the men's record set by Swedish technical specialist Ingemar Stenmark in the 1970s and 1980s.
"Every day is a new chance to break my own record which is kind of weird to say but it still makes it exciting," the 31-year-old Vonn told reporters. "And my dad is here so it's really special."
While many of the racers struggled to keep their line, World Cup leader Vonn put in a flawless run to claim her 38th downhill victory on the circuit.
"I know a lot of girls were having some trouble with the bumps and it was very flat light in some sections but I think I just executed well in the right places and was able to carry my speed through the course," Vonn said.
Switzerland's Fabienne Suter, fully recovered after tearing a muscle above the knee a month ago, was second, 1.51 seconds behind, while local racer Viktoria Rebensburg was third.
Vonn extended her overall World Cup lead over Switzerland's Lara Gut, who finished a disappointing 14th, to 127 points and will go for win number 77 in Sunday's super-G in this German resort.
(Writing by Clare Fallon, editing by Pritha Sarkar)
