Bayern Munich beat Barcelona 4 - 1 in the first leg of its Champions League campaign . Thomas Muller scored twice with Mario Gomez and Arjen Robben also on target . Last year 's defeat by Chelsea at its home stadium still hurts , as does the memory of losing out to Inter Milan two years ago , but that pain and anguish has driven Bayern to the brink of history . Bayern boss warns against complacency ahead of second leg . Barcelona 's Gerard ##o believes ` ` almost impossible '' for his side to progress .
Bayern Munich beat Barcelona 4 - 1 in the first leg of its Champions League campaign . Thomas Muller scored twice with Mario Gomez and Arjen Robben also on target . Bayern boss warns against complacency ahead of second leg . Barcelona 's Gerard ##o believes ` ` almost impossible '' for his side to progress .