In a pan, crush remaining 1 cup blueberries and stir in sugar; cook over medium heat, stirring, until sugar is dissolved.
Stir together cornstarch, water and lemon juice; add to blueberry mixture along with cinnamon. Cook stirring, until mixture boils and thickens; spoon over blueberries in baked pie crust. Refrigerate at least 1 hour or up to 8 hours.
Serve with fresh whipped cream, whipped topping or vanilla ice cream.