The United States trounced Britain 14-0 to open the tournament, while Australia downed China 3-1.
Fujimoto was ruled safe on a play at the plate after Robin Mackin's pitch sailed over the catcher and to the backstop.
Alison Bradley drove in Canada's only run with a single in the sixth inning.¤
Jessica Mendoza homered twice and drove in six runs, and three pitchers combined on a five-inning one-hitter as the U.S. beat Britain in a game called because of the run rule, the AP reports.
Last year, the United States lost its first World Cup game to Canada 2-1 for its first international defeat in three years. The Americans eventually lost in the tournament final to Japan.
Mendoza hit a two-run homer over the right-field wall in the first inning, and lofted another blast over the outstretched glove of right fielder Laura Thompson to cap a six-run third. It was the first time Mendoza has homered twice in the same game for the U.S. team.
Monica Abbott pitched three perfect innings before yielding to Alicia Hollowell, the winning pitcher in this year's Women's College World Series. Jennie Finch, two months removed from the birth of her first child, struck out the first two batters she faced before Terra Davenport grounded a single up the middle to break up a no-hitter.