That's exactly my taughts when I knew the stats of their defensive lineup, I mean it's totally amazing seeing that both the attack and defense of this team is so strong, on the other hand their midfield can also be said to have the same strength and ability, I believe it's because all the players of the team don't play a particular fixed role as they rotate and play together as one and it's very hard to mark or even score them.
A somewhat overlooked fact is that PSG have only conceded one goal in this Club World Cup, a 0-1 defeat to Botafogo in the group stage. Since then, PSG have consistently won without conceding, even against Inter Miami and Bayern. And most surprisingly, the match against Real Madrid left everyone baffled. How could they win by such a large margin without conceding? This demonstrates the significant difference in strength between the opponents PSG faced and PSG itself.
Botafogo is the team that has scored and beaten PSG so far. So, judging by this, Chelsea will have almost the same chances. This suggests that nothing is impossible for a win.