I do not think that PSG vs Arsenal is that big, I mean bigger than most games this round that is for sure, but it's too early of the round, and we have 8 games totally this time in UCL so it will be six more games after this, so it doesn't matter if one of them wins or they draw, it will not be great and we are not going to see anything changing much, if this was a knock out stage then it would be fun but right now it is not and we are not seeing it change at all.
Plus, there are only very few teams that these bigger clubs play against big clubs, most of the games they play against are against weaker teams, so they are all expected to be doing fine, either top eight or close, so it shouldn't really be a problem to even lose.