Heat the olive oil in a large saucepan over medium heat.
Add the chopped onion and sauté until translucent, about 5 minutes.
Stir in the minced garlic and cook for an additional 1 minute, being careful not to burn it.
Add the diced carrot and celery, cooking for another 5 minutes until they become tender.
Pour in the crushed tomatoes and add the tomato paste. Mix well to combine.
Season the sauce with oregano, basil, salt, pepper, and sugar (if using). Stir to integrate all ingredients.
Bring the sauce to a simmer, then reduce the heat to low and let it cook uncovered for about 20 minutes, stirring occasionally.
Taste and adjust seasoning if necessary before serving.
Serve hot over cooked pasta and garnish with fresh basil leaves if desired.