Natalie Spooner scored a power-play goal in the third period to break a 2-2 tie, and Canada went on to beat the United States 4-2 at the Four Nations Cup on Wednesday.
Haley Irwin, Melodie Daoust and Brianne Jenner also scored for Canada, which improved to 2-0 at the tournament.
Genevieve Lacasse, who made 21 saves for Canada, said her team's physicality overwhelmed the Americans.
"I really think it's our battling," she said. "We were first to the puck in the corners and we were just battling hard along the boards. We weren't scared to take a hit, we weren't scared to give a hit. That really came a long way."
Kelli Stack and Lyndsey Fry each scored and Jessie Vetter stopped 24 shots for the U.S. (1-1) one day after they shelled Sweden 10-0.
Lacasse said Canada showed some unselfishness with a number of blocked shots as the Americans tried to put on pressure late in the third period.
"A lot of their shots were from the outside and stuff like that. We really took away their time and space. Didn't let them in the slot or anything like that, so it was a huge team effort and got lots of bruises from blocked shots, but that's what it takes to beat them," said Lacasse.
The game came a day after forward Meghan Agosta-Marciano was critical of the team's forechecking in Canada's 3-1 win over Finland.
Head coach Dan Church said that issue was resolved against the Americans.
"Definitely. I think it was a 180-degree turn from how we played last night," he said. "We chipped pucks past the U.S. all night, made their defence have to turn and get back to pucks, and put their goalie under pressure with a lot of good forecheck pressure.
"That was probably one of the critical factors in the game, that chipping it past their 'D' puts us into a lot of battles, spots on the ice where our size and strength can make a difference."
Canada finishes the preliminary round against Sweden on Friday. The Swedes are 0-2 after losing 2-0 to Finland on Wednesday.
Canada is playing at the tournament without six key veterans including star forward Hayley Wickenheiser, while the Americans were also sitting some veterans. Both teams are evaluating talent ahead of February's Winter Games in Sochi, Russia, where they are perennial favourites to play for gold.
Canada twice beat the U.S. in exhibition play in October. Church said the games are giving his side a good idea of how the Americans will play in Sochi.
"There's always a bit of cat and mouse and things that you hold back and change, so they don't get a full complete picture of what you're doing and what you're trying to accomplish. ...," said Church. "So I think we do have a good sense of who they are as players but I think we'll learn more as we move along as well."
The game also gave Church his first look at Lacasse in an international game that mattered.
The 24-year-old Kingston, Ont., native is vying for Olympic starts with Shannon Szabados and Charline Labonte. Szabados started for Canada when the team won gold against the U.S. in 2010, but Church said Lacasse has just as much of a shot as her teammates at starting in next year's final.
Lacasse said she doesn't expect to be on the ice for that game.
"I don't think so. I'm the underdog, I'm the young one coming in. So there really aren't that many expectations for me," she said.
"I just go out there and practise and try to bring some fun to the team, and bring that light energy, but when it's time to get to business it's business time. All three goalies get along super well ... we know that whoever's in net will do the job."