I am not surprised by the one-goal defeat to PSG because in this group phase PSG only needs to secure itself to be able to qualify for the next round because in the group occupied by PSG there are also strong teams like Atletico Madrid.
This competition have just been giving a lot of surprising results as a lot of top European teams have been losing matches to smaller teams. We saw how Real Madrid dropped points, PSG the most in form team dropped points. The competition is very unpredictable as the players have had a very long season without much rest which I think is the main reason why these teams are not performing so well as we expect. I believe when we get to the knock out stages it will be a whole different and most teams will be more serious.
It appears I spoke too soon.

Flamengo now lead 2-1 with less than 15 minutes to go. I’ve been really impressed by them actually.
This is a very surprising game, everything happened really fast and to be serious I was really surprised how things turned around so fast. Flamengo really played well and I am impressed as well but I believe Jackson's red card made it worse for Chelsea.