Add some red wine to the sauce.
If the sauce seems to thick, add some tomato juice, tomato passata or stock. If the sauce is too thin, mix some corn flour with cold water and add that the sauce, which will thicken when boiling again.
For an even more intense tomato flavour, cut real tomatoes in half and sprinkle with salt, pepper, oil and herbs. Roast them in the oven until charred. Add them to the sauce before blitzing.