Since claiming downhill gold at the 2011 World Championships in Garmisch, Guay has found the top step of the podium hard to come by.
But the 32-year-old was back to his best in Italy as he came home in 1:56.65 minutes for the win, 0.12 seconds ahead of nearest challenger Kjetil Jansrud of Norway.
This was Guay's fourth World Cup victory and his 20th podium finish, meaning he now sits joint top of the Canadian all-time record alongside Steve Podborski.
Completing the podium in Val Gardena was Frenchman Johan Clarey as he came home in 1:56.89 minutes.
Guay now sits second in the downhill World Cup standings on 147 points, 53 behind leader Aksel Lund Svindal after the Norwegian finished fourth in Val Gardena with Italian Dominik Paris third on 129.
© Sportsbeat 2013