Trim and tie top sirloin roast.
Pat roast dry with a paper towel and rub evenly with 4 teaspoons kosher salt.
Refrigerate uncovered for 1 hour or up to 24 hours.
Place oven rack at the lower-middle position and preheat oven to 275 degrees.
Use a roasting pan, and a V-rack inside of pan.
Spray V rack with vegetable oil.
Remove roast from refrigerator, and pat any excess moisture off with a paper towel.
Season with 1 Teaspoon black pepper, spread evenly over the roast.
Heat oil in a heavy bottomed pot, or dutch oven, on medium-high heat, and brown the roast on all sides, 8-12 minutes per side.
Once browned on all sides, remove from pot, and transfer to prepared roasting pan with V-rack. Set pot aside with drippings to be used later.
Roast until the beef registers 120-125 degrees F (1 ½-2 hours cooking time).
Meanwhile, while the roast is in the oven, add mushrooms to the heavy bottomed pot, or dutch oven, and cook over medium-high heat until soft and golden brown.
After 5 minutes, add in the onions, carrot, and celery and continue to cook an additional 8 minutes, until everything is lightly browned and softened.
Add flour, onion powder, garlic powder, garlic, and tomato paste to the pot, and stir together, cooking for another 2 minutes.
Slowly stir in wine and broth, scraping any browned bits off the bottom, and whisking or stirring to get rid of any lumps.
Bring to a boil. Then reduce heat to medium, and let simmer until thickened, about 10 minutes.
Strain through a fine mesh strainer over a bowl, to make a lovely gravy. Discard what is in the strainer.
Stir in Worcestershire sauce, and season with salt and pepper to taste.
When roast is done to your liking, (120-125 degrees is medium-rare, cook longer if you want it done more), then transfer from roasting pan to a carving board, and loosely cover.
Let it rest for 20 minutes, for the center to continue cooking, and for the juices to reabsorb.
After 20 minutes, remove twine, and slice roast beef into ¼ inch thick slices, and serve with gravy spooned over the top.