It also washed away whatever doubts and bad taste remained from Finland's upset of the U.S. team in November.
It allowed their best offensive player, Amanda Kessel, to test her nagging hip injury in what was an encouraging return from 10 inactive months.
And, maybe most important, it proved that these Americans were determined enough to avoid looking beyond the opener toward Wednesday's showdown with Canada, their increasingly bitter rival for the gold medal.
The game was the first played under new Olympic guidelines dictated by a decade-and-half of American and Canadian dominance. At previous Games, the two teams typically embarrassed their other opponents en route to an inevitable gold-medal showdown.
Canada, for example, opened the 2010 Olympics with an 18-0 rout of Slovakia.
Now, the top four teams in the world rankings - in this case, Canada, the United States, Switzerland, and Finland - share the same round-robin pool, while the four other qualifiers share another.
"I think it's better," said Kelly Stack, the U.S. forward who scored her team's second goal. "It's nice for the teams at the top. You get to play better competition right away, and you don't see those blowout games. It gets us more prepared for our next game."
The Americans will face Switzerland on Monday before taking on the Canadians.
Canada, which opened here with a 5-0 win over the Swiss, engaged in two brawls with the Americans during this Olympic run-up.
Though the United States, considerably quicker than its opponents, outshot them by 43-15, the Finns, with goalie Noora Raty, were no pushover.
In her team's Lake Placid victory, Raty stopped 58 shots.
"She's such a good goalie," said Stack. "She covers up the whole net."
If there were any nerves, they disappeared early when Hilary Knight beat Raty on a breakaway less than a minute into the game.
"Anytime you can strike quickly, it helps everyone. They can take a deep breath and get rid of the nerves," said U.S. coach Katey Stone.
Seven minutes into the second period, Stack made it 2-0, slapping a rebound out of midair.
"It hit me in the chest, and I just sort of swatted at it," she said. "Noora's such a great goaltender you've got to try to get it by her any way you can."
The lead grew to 3-0 later in the period on a goal by Alex Carpenter, whose father, Bobby, was an NHL star.
The only shot the Finns got past Jessie Vetter came from Susanna Tapani with just under five minutes left.
And so the Americans avenged one recent slap in the face. On Wednesday they will meet the team that, both literally and figuratively, has punched them there.