At Red Bull Arena, PSG led early through Angel Di Maria’s close-range strike, but they fell apart after the Argentina international missed a first-half penalty.
Before half-time former PSG midfielder, Christopher Nkunku leveled and an Emil Forsberg penalty completed the turnaround in a game that then saw Idrissa Gueye and Presnel Kimpembe sent off for the visitors.
Leaving last season’s finalists facing a significant challenge to progress to the 2020-21 knockout stages, PSG is three points behind leaders Manchester United and Leipzig, with back-to-back defeats in Group H.
But Tuchel rejected talk of his position is under threat and any notion that tension between him and sporting director Leonardo is affecting performances.
“It was a tight, difficult game, very physical. We started well and managed to create numerous chances. We missed a penalty, and they scored theirs. That’s probably what the difference was. After the first red card, it became very difficult. We managed to use the ball well, and we embraced the physical battle, so not everything is negative. But in the Champions League, you need to take your chances, and we didn’t do that tonight.”
