Hilary Knight and Kendall Coyne Schofield also scored for the Americans while goalie made Alex Rigsby made 31 saves. Pankowksi put a slap shot over Emerance Maschmeyer's right shoulder at 14:03 of the second period for a power-play goal.
"We always want to come and kind of take the game to them and play our game," Pankowski said. "They also make it hard because they have so much skill and so much speed."
Canada had a power play with 2 ½ minutes to play, but it was negated by Natalie Spooner's hooking penalty with a minute remaining.
Brianne Jenner had goal and an assist in her 100th career game for Canada. Sarah Nurse also scored and Brigette Lacquette assisted on two goals. Goalie Emerance Maschmeyer turned away 27 shots.
The Canadians scored both goals on power plays but went 2-for-7 overall. The U.S. was 1-for-6.
"I think special teams wins hockey games," Nurse said. "And I think on our power play specifically, we had a lot of good chances and we did capitalize on it. We'd like to capitalize on a couple more."
All Group A countries and the top three Group B countries will play quarterfinals April 11. The semifinals are April 13 followed by medal games April 14.
More AP sports: https://apnews.com/apf-sports and https://twitter.com/AP—Sports