Add olive oil to a large saucepan over medium-high heat.
Season roast with salt and pepper, to taste.
Place roast in pan and sear on all sides.
Remove from saucepan and place in a slow cooker sprayed with nonstick cooking spray.
Cover roast with carrots, celery and onion.
In a bowl, mix together balsamic vinegar, tomato juice, beef broth, garlic, thyme, and sage. Pour over the roast.
Place 2 bay leaves on top and cover with lid.
Cook on low for 9-10 hours.
When done cooking, remove roast and vegetables and keep warm.
Skim the fat off the liquid and pour liquid into a saucepan over medium-high heat.
In a small bowl, whisk together corn starch and cold water; pour into the saucepan and mix well.
Bring to a boil and let cook for a few minutes or until it starts to thicken.
Serve gravy with pot roast and vegetables.
Notes
For any leftover tender roast, let it cool down to room temperature, and then place the leftovers in an airtight container and store it in the fridge for up to 4-5 days.