U.S. pitcher David Huff tried to pick off Pete Orr at first base, but his throw went into right field to score Skyler Stromsmoe. The right-fielder's throw to third then went wide, allowing Orr to score the winning run as the Canadians beat the Americans for Pan Am gold for the second straight Games.
The international tie-breaker was put in place in extra innings, meaning each team begins the frame with runners on first and second.
The U.S. had taken a 6-4 lead in the top of the 10th with Tyler Pastornicky's two-run single off Chris Leroux.
Orr cut the deficit to 6-5 when his single off Huff scored Tyson Gillies.
Rene Tosoni hit a three-run shot for Canada and Jordan Lennerton had a sacrifice fly for his team-leading ninth run batted in of the tournament.