Going out of such a big group stage — where even Belgian side Club Bruges is ahead of PSG — would set a new low for the cash-rich, Qatari-backed club. PSG's owners, QSI, have spent fortunes trying to turn PSG into a dominant European club.

Four years ago, in 2020, Bayern Munich beat Paris Saint-Germain 1-0 in the Champions League final. Tonight, they meet for the third time since. Those four years — an Olympic cycle, a World Cup cycle — is a period of time that lends itself to assessing how the two clubs, which share as many similarities as differences, have changed.

PSG manager Luis Enrique said on Monday that his team have put themselves in a "difficult" spot with a slow start to their Champions League campaign.