Wall bounced the double off the right-field fence after back-to-back walks were issued to pinch-hitter Ella Matteucci and second baseman Nicole Luchanski to start the bottom of the seventh inning.
"With Bradi, you know that something is going to happen," said Andre Lachance, Canada's manager. "She rarely strikes out, she puts the ball in play, she got a good ball to hit and it was a shot. That's what happens with Bradi at the plate, or with the middle of our lineup - you bring them to the plate and they're going to do some damage."
The win was the first of four exhibition games for the Canadians before they head to Miyazak. Japan, for the Women's Baseball World Cup.
Japan got out to an early lead on Sunday, cashing in three runs in the first inning, thanks to a bases-clearing triple from the squad's No. 6 hitter. Kate Psota got the Canadians on the board in the first with a one-out RBI-single to left field, her first of two hits on the day.
Right-handed pitcher Heidi Northcott got the start for Canada, throwing two innings and allowing three runs on two hits with two walks and a strikeout.
Meagan Cornelsson took care of Canada's early deficit, driving in two runs in the third frame with a two-out double. Vanessa Riopel pitched three scoreless innings of relief for Canada, walking four and hitting one batter but allowing no hits.
The Japanese high schoolers regained the lead in the top of the sixth inning, plating a leadoff walk after a sacrifice bunt advanced the runner.