I was also expecting both teams to score, but Paris Saint-Germain came very close to scoring in a few attacks, but two of their balls hit the post. That's why they couldn't get close to scoring. If there had been a goal instead of a post, the match could have even ended in a draw. To be honest, Arsenal deserved to win the match. Because Arsenal played with more passion and quality than Paris Saint-Germain. Of course, Dembele is a player whose absence can be felt. This weakened their attacking area.
Arsenal is really lucky that PSG didn't score two goals, after Arsenal have successfully scored 2 goals, they're using their dirty strategy again i.e. park the bus. Arsenal not dare to score many goals unlike other teams which make the match looks not exciting to watch.
Dembele want to show if he's a star player and he want to become the next Mbappe, but Luis Enrique didn't want that to happen.
This is not good for both of them, I guess it's better for PSG to find new player that can replace Dembele, Dembele might want to leave in the next season.
Dembele had a great start and has already scored 4 goals and given 3 assists and Dembele already has more goals than he had last season, so his suspension looks like a weakening of the team and Arsenal couldn't help but take advantage of that.
Of course if the success of the team depends on a player like Dembele, then apparently the team is not doing well, because Dembele with all due respect is not Mbappe, Bellingham or even Vinicius, he is a good player, with quick feet but very average other characteristics.
Also Donnaruma helped a lot to Arsenal, cause Donnaruma decided to concede goals like young players do after the academy in their first matches, especially the offensive second goal which a goalkeeper like Donnaruma should have deflected.
Without their key player at the moment and with such goalkeeping errors, PSG were apparently doomed to defeat.