Preheat oven to 220C/450°F.
Combine the oregano, thyme, Rosemary, salt, black pepper, and mustard powder in a bowl then rub evenly on the top round roast.
Place the roast in a shallow roasting pan fitted with a rack.
Roast for 15 minutes, then reduce the oven temperature to 180C/350°F. Roast for around 50 minutes, or until the beef reaches an internal temperature of 140°F.
Remove the roast from the oven and tent it loosely with foil. Let the meat rest for 10-15 minutes before carving against the grain.
