The forward picked herself up after being brought down by defender Manuela Vanegas to send goalkeeper Catalina Perez the wrong way from the spot.
Pia Sundhage is the first female coach to lift the trophy, Brazil winning for the eighth time in nine tournaments.
Her side scored 20 goals in six games, conceding none, en route to the title.
The winners were awarded $1.5m (£1.23m) in prize money, while the runners-up received $500,000 (£410,000).
By finishing in the top three, both teams have qualified for the 2023 World Cup, and by making the final, they have secured their places at the following year’s Paris Olympics.