Monique Lamoureux, Emily Pfalzer, Haley Skarupa and Hilary Knight also scored, while Alex Carpenter picked up two assists.
Molly Schaus made 14 saves to get the shutout for the U.S., which like Canada has left some of its veterans at home in hopes of developing some of the country's younger talent.
Eveliina Suonpaa stopped 35 of 40 shots in taking the loss for the Finns, who will meet Sweden on Wednesday.
Finland upset the U.S. in the preliminary round of last year's tournament to deny the hosts a top-2 finish for the first time in the tournament's history while claiming the country's first silver.
There would be no repeat in 2014 as the Americans led 1-0 after the first and 3-0 in the second before adding two more in the third.
The United States went 1 for 6 on the power play while Finland failed to score on three chances with the man advantage.
Later tonight, Canada opens its tournament against Sweden before meeting the Americans on Wednesday.
The Canadians have won gold 13 times in the tournament's 18-year history — including in 2013. The United States is the only other country to claim gold at the tournament, having done so five times. Finland's best finish is silver while Sweden has never finished higher than third place.