Finely chop the onion, celery and carrot and set aside. Peel the garlic clove but keep it whole.
Season the chicken well with salt and pepper.
In a heavy bottom pan (this was a wedding gift to me - one of my favorites - and this is what I use. Anything similar will do) and heat the olive oil over medium heat.
Brown the chicken on both sides in batches, being careful not to crowd the pan, starting with the skin side down. Once the chicken is browned, set aside in a shallow dish where the juices will collect. If the bottom of the pan is burning, turn the heat down slightly.
If there is no more oil in the bottom of the pan, add an extra tablespoon and add the chopped onion, celery and carrot. Season well with salt and freshly ground black pepper. Sauté over low heat, until the onions turn translucent and the soffritto (as this mix of vegetables is called) begins to brown, about 10 minutes or so, scraping the bottom of the pan to remove all the brown bits. Add the whole garlic clove, sage and rosemary and cook for another 2-3 minutes until fragrant.
Return the chicken and its juices back into the pan and add the red wine. Cook over medium heat until the red wine is almost reduced completely, meaning evaporated, about 10 minutes more.
Pour the can of tomatoes into a bowl and crush them with your hands to bread them up. Add the tomatoes and their juices to the pan and cover. Reduce the heat to low, and simmer very gently for about 30 minutes, stirring every 10 minutes or so.
At this point, the tomato sauce should have reduced some but not enough. Remove the chicken and gently simmer the sauce without the lid until it has thickened and reduced by a significant amount (it’s hard to determine the exact cooking time because it depends on the type of pan you are using and the temperature but you are looking for a good, thick sauce that will cover the chicken but not too much that it will swim in it). Return the chicken to the pot.
Test for seasoning and add salt and pepper, if need be.
Serve the chicken immediately, or gently reheat before you are ready to eat.