Lewandowski settles nine-goal thriller

Bongarts

Leon Goretzka's early header had Bayern in front at the Allianz Arena but Niklas Sule was sent off and Robert Glatzel and Marc Schnatterer scored to give the second-tier side a shock half-time lead.

Lewandowski was benched due to illness but within 11 minutes of his introduction as a half-time substitute he had set up Thomas Muller and turned in from close range to put Bayern ahead.

Serge Gnabry seemingly ended Heidenheim's hopes by converting a corner but Franck Schmidt's men improbably hit back with Glatzel scoring twice to draw the scores level at 4-4 and complete his hat-trick.

There was more drama to come, though, as referee Guido Winkmann harshly pointed to the spot when Marnon Busch hand-balled in the box, Lewandowski staying calm to settle matters with six minutes to play.

Bayern join RB Leipzig and Hamburg in the draw for the semi-finals, but this was more exertion than Niko Kovac would have wanted ahead of the crunch clash with Bundesliga title rival Borussia Dortmund.