Victoria Bach, Sarah Potomak, and Stephanie Lalancette also scored to help Canada earn a bye into Saturday's semifinal.
"It's a great feeling," Sauve said of her first shutout while wearing a Canada jersey. "But to be honest, I couldn't have done that without the team in front of me. They played great; they were very strong defensively throughout the whole game."
Canada had to stay strong in their own end, as the Czechs managed 12 shots on net in the first period.
The Canadian squad scored its first goal 1:42 in the second period, when Bach cracked the scoreboard on an assist from Breanne Wilson-Bennett.
Wildfang followed up with her first goal just over a minute later to make it 2-0 going into second intermission.
"The team (had) been working really hard all game, and we knew that we needed to stay focused," Wildfang said. "My first goal came from a beautiful pass from my linemate, Rebecca Leslie, and she couldn't have made a more perfect pass to me, and it found the back of the net."
Canada kept up its momentum in the third as Lalancette added a goal at 4:06 in the period, Potomak scored a power-play goal at 8:16 and Wildfang added her second of the game with three minutes to go.
"The second one, I got another beautiful pass from my D-partner Ainsley MacMillan, and I had a great line standing in front of the goalie to block her eyes," Wildfang said. "We're proud of our accomplishment tonight … Now we have to get refocused for what's to come."
Canada will play one of two winning teams from Thursday's quarter-finals on Saturday.