With Gina Lewandowski returning from injury to help balance out regular starters Tymrak and Brooks returning to the US after their loans expired, Bayern got off to a fast start at the historic Grünwalder Stadion.
Direct play lead to a corner which Sarah Romert sent into the box. Lewadowski headed in the cross off the post to give Bayern the 1-0 lead only seven minutes in.
Only 12 minutes later, Potsdam equalized in the same way, scoring a header off a corner. The goal was scored by Turbine's Hegerberg, assisted by Evans, and the direct play would thereafter devolve into long ball after long ball until halftime.
Unfortunately for FCB, Lisa Evans wasn't done there. In the 49th minute, she found herself on the ball in the penalty area. She then floated her shot over Bayern's Längert, giving die Potsdamerinnen a 1-2 lead.
Bayern pressed further but were eventually caught out on the counterattack by Evans once more, forcing Niki Cross into a tackle which saw her sent off as the last defender preventing a goal-scoring opportunity.
Former Bayern-Mädel Julia Simic played 70 minutes for Potsdam before being replaced by Cramer.
Bayern have an even more important match on Wednesday against VfL Wolfsburg, and a loss there could see most hopes for a trophy this season dashed. Everything to gain for FCB Frauen at the moment, and most to play for as well.
Currently, FCB sit 4th, 8 points off second place Potsdam and 9 points off leaders Frankfurt. Next opponents Wolfsburg are in 3rd, 7 points above.