Season brisket, as desired. Brown 60 to 90 minutes in 350-degree oven.
Combine wine, water, ketchup, onions, pimiento and mushrooms. After meat is browned, pour mixture over meat and cover tightly with foil.
Bake at 350 degrees until meat is tender, approximately 2 to 2-1/2 hours. Let cool. Separate meat from sauce and place sauce in bowl. Put meat and sauce in refrigerator overnight.
Next day, remove any excess fat from sauce. Slice cold meat with electric knife on diagonal. Put slices back in pan and pour sauce over; reheat. Put meat on serving platter and pour sauce on top.