The Bayern sporting director and the BVB coach clashed on the touchline in the aftermath of Rafinha's red card in a heated affair at the WestfalenstadionBorussia Dortmund and Bayern Munich was a feisty one, with the referee Peter Gagelmann dealing out a number of bookings.
Things came to a head midway through the second half when Rafinha picked up his second booking in a number of minutes for lashing out at Jakub Blaszczykowski.
That turned out to be boiling point. Minutes later, Matthias Sammer and Jurgen Klopp were engaged in a heated argument on the touchline before being pulled apart and forced to apologise.
The two sides eventually recorded a 1-1 draw, with Mario Gomez's header cancelling out Kevin Grosskreutz's early volley.