Melissa Gonzalez scored on a penalty corner 21 seconds into the match to set the tone on a rainy Wednesday evening. Katie Bam scored the first of her three goals four minutes later.
Katie Reinprecht scored late in the second period to make it 3-0 at halftime. Jill Witmer scored for the United States in the third period, and Bam scored twice in the fourth.
The Americans improved to 3-0 and moved to the top of Pool B by moving ahead of Britain in goal differential.
The United States will face India on Thursday and will close pool play with a showdown against Britain on Saturday.