The Kandahar course has been modified slightly to return to its original design but the 30-year-old from Mont-Tremblant, Que., Guay still had the fastest time of one minute 57.08 seconds.
Adrian Theaux was second to lead three Frenchmen in the top 10 by covering the 3,256-metre course in 1:57.15. Swiss ace Didier Cuche was third in 1:57.45 as he attempts to follow up his win in Kitzbuehel with a victory on another classic course in his final season.
Cuche was runner-up to Guay last year.
"I feel comfortable on this course. I prefer it to last year, when it was really icy," said Cuche, who won the Garmisch downhill eight years ago.
The top Austrian was Hannes Reichelt in a tie for fourth with Andrej Sporn of Slovenia.
Reichelt was the silver medallist in the super-G last year in Garmisch-Partenkirchen and is the probably the team's best hope for its first win this season on a speed race.
"There are a lot of other guys," Reichelt said.
Mild and sunny weather has made the course bumpy but the racers said it was in better shape than Thursday.
"It was much better. Yesterday, there was the danger that it would break up. Now, it's like the real Garmisch course," Reichelt said.
Bode Miller ended up in ninth place.
A downhill is slated for Saturday, followed by a super-G on Sunday.