Poor defending let Hertha Berlin down in a 4-1 loss at Freiburg which leaves the big-spending Berlin team 14th in the 18-team league, and with one win in its last six games.
Bundesliga: Robert Lewandowski breaks goalscoring record; Erling Haaland brace helps Dortmund secure second place
It means Dortmund are assured of second place with one game of the season remaining. Despite defeat, Leipzig are virtually assured of Champions League football next season.
Bundesliga: Robert Lewandowski's brace rescues defending champions Bayern Munich from defeat against Hertha Berlin
A Robert Lewandowski brace was not enough to save Bayern Munich from making a spluttering start to their title defence as they were held to a draw by Hertha Berlin.
Bundesliga: Borussia Dortmund stunned by relegation-threatened Fortuna Duesseldorf; Thorgan Hazard stars in Gladbach's win
The defeat saw Dortmund's lead at the top of the table shrink to six points after Thorgan Hazard inspired Borussia Moenchengladbach to a win against Nuremberg.