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 . Robert Lewandowski opened the scoring vs his former club on 36 minutes . Dortmund applied much of the second-half pressure but were kept at bay . Bayern restored their 10-point lead at the top of the Bundesliga .