Even scoring one goal can earn you three points. That's exactly what happened in this Paris Saint-Germain match. Vitinha scored the winning goal for Paris Saint-Germain Adana. Paris Saint-Germain fought hard and created numerous chances, but they only managed one goal. This shows they need to improve their attacking performance. So far, it seems like Paris Saint-Germain isn't taking advantage of their opportunities. I was expecting at least three goals from them against Nantes.
I think that PSG are not too worried about Ligue 1 because they are almost certain they can win it without much competition. That’s why their approach to Ligue 1 games is more relaxed, especially since it’s only the start of the season. It’s clear that the team hasn’t yet reached their maximum condition, which is why the wins may be less convincing. Although, as you said, even a one-goal victory is still 3 points.