Robert Lewandowski returned to haunt his former club as Bayern Munich earned a narrow victory against Borussia Dortmund at the Signal Iduna Park on Saturday . Poland international Lewandowski scored the winner on his first visit back to the club he left on a free transfer last summer as Pep Guardiola 's side restored their 10-point lead at the top of the Bundesliga . Lewandowski spent four years at Dortmund , leading them to back-to-back league titles during that period , and offered only a muted celebration when he pounced to give the visitors the lead 10 minutes before half time . Robert Lewandowski beats Marcel Schmelzer to the ball to head Bayern Munich in front against Dortmund . The Bayern players celebrate in front of the travelling supporters after claiming a narrow victory . Roman Weidenfeller saved Thomas Muller 's original effort bu the ball fell kindly to the Poland striker . Weidenfeller complains to his defence as Lewandowski makes his way to his feet after scoring . Dortmund ( 4-2-3-1 ) : Weidenfeller ; Sokratis , Subotic , Hummels , Schmelzer ; Bender , Gundogan ( Mkhitaryan 79 ) ; Blaszczykowski ( Kagawa 67 ) , Reus , Kampl ( Ramos 67 ) ; Aubameyang . Subs not used : Kehl , Langerak , Ginter , Dudziak . Booked : Aubameyang , Schmelzer . Bayern Munich : Neuer ; Benatia , Boateng , Dante ; Rafinha , Lahm ( Thiago 69 ) , Alonso , Schweinsteiger ( Rode 58 ) , Bernat ; Muller ( Gotze 79 ) , Lewandowski . Subs not used : Pizarro , Gaudino , Reina , Weiser . Booked : Schweinsteiger , Alonso , Rode . Scorer ( s ) : Lewandowski 36 . Bayern suffered a shock 2-0 home defeat by Borussia Monchengladbach before the international break but responded to get their title charge back on track against their former championship rivals . Dortmund were unbeaten in their last eight domestic matches , sitting comfortably in mid-table after rescuing a desperate-looking situation earlier this year that saw Jurgen Klopp 's side bottom of the table . But they were behind after 36 minutes against Bayern . Thomas Muller was released down the left channel but his low drive , after bursting towards the box , was parried by Roman Weidenfeller . Unfortunately for the Dortmund goalkeeper the ball rebounded invitingly for Lewandowski to beat Marcel Schmelzer to the ball and head home from 12 yards . Dortmund offered a spirited fightback as the hosts applied much of the second-half pressure , but the Bayern defence held firm although they had Manuel Neuer to thank after saving brilliantly from a Marco Reus free kick in the closing stages . As his team-mates roared wildly around him Lewandowski did not celebrate against his former club . The goal did , however , send the Bayern bench into raptures although Pep Guardiola remained calm . Goalscorer Lewandowski holds off the challenge of Dortmund's Kevin Kampl . The teams line up to observe a minute silence for the passengers of the Germanwings flight that crashed .
Bayern Munich beat Borussia Dortmund 1-0 in the Bundesliga on Saturday . The result means that both teams are level with each other at the top of their respective leagues and will meet again next weekend for a second leg in Munich.