The goal was the 147th of Sinclair's career, and she could have had two if her penalty shot in the first half wasn't saved.
"The win felt incredible and that was the most important thing to come out of today," said Sinclair. "Not only the victory but the way our team played, I thought it was the best we've played all year."
Adrianna Leon opened the scoring just eight minutes into the game on a volley off a headed pass from Sophie Schmidt.
Sinclair was robbed of a penalty right before halftime when Scottish goalkeeper Gemma Fay dove to her right to make the save.
"I've missed a few. It happens," said Sinclair. "I think it's my third or fourth miss with the national team. John (Herdman) said, 'You didn't want to score with a penalty anyway, you wanted a real goal.'"
Sinclair would have her revenge 13 minutes into the second half when she was played in on the left side and had plenty of time to put the ball past Fay, who was one-on-one against Sinclair.
Canada's next game in the tournament takes place Sunday when they take on Chile before rounding out the group stage against the hosts.