My favorite for sirloin roasts.
Try this one. I like to use coatings rather than bacon or extra fat. I also cook using a meat thermometer. About 150 degrees internal temperature keeps it nice and moist. This is slightly above rare but if you will let the meat rest for about 10 minutes before serving it will keep it from being bloody.
Mix 2 parts Flour and 1 part powered mustard with cider vinegar to make a thick paste.
Slice a couple of cloves of garlic and stick in holes in the roast. Salt and pepper. Coat the roast with the mustard mixture, about 1/4" thick. Bake at 500 degrees for 20 minutes or until the coating is brown.
Use 1/2 quart of canned tomatoes, celery, onions, bay leaf, and a good white wine. Chop fine or puree mixture in a food processor. Reduce heat to 350 degrees and pour over roast. Cook to an internal temperature of 150 - 160 degrees basting with tomato mixture frequently.