The Bundesliga side claimed a narrow 1-0 win at Rot-Weiss Erfurt in their first competitive fixture of the 2017-18 season.
Nadiem Amiri scored the only goal of the game 10 minutes into the second half.
Julian Nagelsmann’s team host Liverpool in the first leg of their play-off tie on Tuesday night before travelling to Anfield for the return match eight days later.