Arjen Robben, Robert Lewandowski and David Alaba scored as Bayern consigned Dortmund to a fourth Bundesliga match without a win.
Bayern Munich extended their lead at the Bundesliga summit and dealt another blow to rivals Borussia Dortmund with an impressive 3-1 Klassiker win at Signal Iduna Park.
A fourth top-flight win in succession since the return of coach Jupp Heynckes opened up a six-point advantage over rivals Dortmund, who slipped to third after RB Leipzig - four back from Bayern - beat Hannover 2-1 earlier on Saturday.
Bayern's trajectory starkly contrasts with that of BVB, who have seen their five-point lead after seven matchdays vanish and their hopes of Champions League progression all but dashed amid a run of just one win in seven in all competitions.