Grate the cucumber using a box grater.
Squeeze excess moisture from the grated cucumber.
In a mixing bowl, add the Greek yogurt.
Add the squeezed cucumber to the bowl with yogurt.
Mix in the minced garlic.
Drizzle in the olive oil and vinegar.
Add the chopped dill and season with salt and pepper.
Stir all ingredients until well combined.
Taste and adjust seasoning if necessary.
Chill the tzatziki sauce in the refrigerator for at least 30 minutes before serving.