First Ilias Chair scored with a deflected effort from outside the area, while a curled finish from Lucas Andersen midway through the first half made it 2-0.
Leeds tried to up the pressure in the second half but with little effect, with French forward Georginio Rutter pulling a shot wide from the middle of the penalty area.
Scottish forward Lyndon Dykes and Sam Field both scored headers from set pieces in the second half to complete the 4-0 win.
Leeds manager Daniel Farke turned to his bench to try and influence the game and it was one of those substitutes, striker Mateo Joseph, who came closest, seeing his close-range attempt turned wide by Rangers keeper Asmir Begovic.