Preheat the oven to 375 degrees F
1. Press the pie crust into the bottom and up the sides of a 9 inch pie plate.
2. In a large bowl, stir together the sugar, flour and corn starch. Mix in the lemon zest and lemon juice. Gently stir in the blueberries. Pour into the pie crust.
3. In a medium bowl, stir together the brown sugar, oats, flour and cinnamon. Mix in butter using a fork until crumbly. Spread the crumb topping evenly over the pie filling.
4. Bake for 40 minutes in the preheated oven, or until fruit is bubbly and topping is browned. You may need to cover the crust with foil or a pie shield after about 30 minutes to prevent over browning. Cool over a wire rack at least two hours or until room temperature.