Story highlights Former Barcelona coach sees his new team lose German Super Cup to Borussia Dortmund

Two goals for Marco Reus help beat reigning German and European champions

Bundesliga gets underway on Friday August 9 with Bayern taking on Monchengladbach

Pep Guardiola's first competitive game in charge of Bayern Munich ended in defeat on Saturday as Borussia Dortmund ran out 4-2 winners in the German Super Cup.

Two goals from Marco Reus helped Jurgen Klopp's team beat the reigning German and European champions in front of a home crowd at the Signal Inuna Park.

Dortmund always held sway in an absorbing contest but Bayern, minus Franck Ribery and former Dortmund midfielder Mario Goetze, were never far behind.

Klopp's men were gifted the opening goal in the sixth minute when Reus headed home from close range after Bayern keeper Tom Starke -- deputizing for an injured Manuel Neuer -- had fumbled a cross.

Dortmund were unlucky not to double their lead moments later when Robert Lewandowski scored, but he was adjudged to be offside.

Bayern fought back and were denied in the 12th minute by a fine double save by Roman Weidenfeller who blocked Xherdan Shaqiri's low shot before palming away a rebound effort to safety.

The half ended as it had begun with Dortmund with their noses in front but it was Bayern who struck first after the break -- Arjen Robben heading home in the 54th minute to level the scores.

The goal sparked a frantic passage of play which saw four goals in ten minutes.

In the 56th minute, Dortmund regained the lead when Daniel van Butyen scored an own goal and 60 seconds they were 3-1 up thanks to a wonderful curling effort from Ilkay Gundogan.

Bayern halved the deficit eight minutes later when Robben received a cross from Philipp Lahm, before turning and firing a left-foot shot past Weidenfeller.

But it was Dortmund who finally finished the contest in the 86th minute when Reus steered Pierre-Emerick Aubameyang cross into the net to bag a brace and ensure Dortmund made a winning start to the season.

The Bundesliga gets underway on the August 9 with Bayern Munich playing Borussia Monchengladbach at the Allianz Arena. Dortmund kick off their campaign the following day away to Augsburg.