A member of the national team since 1990, Granato scored twice in a three-goal first period and again 4:33 into the third. She has four goals and an assist as the defending gold medalists have opened the tournament with back-to-back lopsided wins.
"She's such a great player and really knows how to move around and create opportunities," teammate Julie Chu said of Granato. "She definitely has the scoring touch."
So does the rest of Team USA, which has outscored its first two opponents, 22-1, and faces unbeaten Finland on Saturday for the Group B title.
Canada also is 2-0 and Hayley Wickenheiser leads the tournament in scoring with three goals and three assists.
Asked if she has thought ahead to a meeting with Canada in the gold medal game, American forward Krissy Wendall said, "I'd be lying if I said they weren't, but right now I just want to concentrate on winning our pool."
The Finns improved to 2-0 on Thursday with a 3-1 triumph over Germany.
Katja Riipi scored a goal and set up the other two for Finland, which had a 39-16 advantage in shots and never was seriously challenged.
Finnish forward Petra Varrakallio said her team has a lot to work on if it wants to compete Saturday.
"I think a team like Germany got way too many scoring opportunities against us, so if there is USA or Canada against us, they will score from those opportunities with a better percentage," she said.