Having champion mentality without quality players also doesn't make sense to win the Champions League. Bayern Munich have good players to defend and attack, and their style of play is very different and that determines the course of the game. But this defeat was influenced by many factors in which in the end I have to admit that PSG was just unlucky with goals and a few chances.
Bayern always have good players and they are smart to choose players for their team. After the injury of Neuer, they wisely picked Yann Sommer who is a very good goalkeeper and experienced a lot of tough matches in Euro and World Cup with Switzerland. The match with PSG shows that he is a very good replacement for Neuer in short term and long term as well.
PSG also has good defense and goalkeeper from Gianluigi Donnarumma, but PSG had to fail and were unlucky when they had opportunities. Without Gianluigi Donnarumma and good defense, I think PSG will concede lot of goals because Bayern Munich attacked well and dominated the match. Some people regretted that PSG didn't make the most of their chances, but I can only say that the team did their best throughout the match.
Yann Sommer had great performance in that match and I admit that. He managed to make 4 good saves when PSG had chances, but Gianluigi Donnarumma
made 5 saves so that 1 goal conceded was not the end of everything for PSG. It seems to me that PSG still have hope to win the second leg and qualify for the quarter-finals, but they need to really improve and be well motivated to put in a good performance.
Even though PSG has expensive players who are also former Champions League winners such as Messi, Neymar and Ramos, basically the PSG squad is not stable enough in their midfielders. The creativity of the midfield is not good enough to support the attacker where quite often the striker has to go down and build an attack from half of his own field.
Both Bayern and PSG have very good players but as a team, PSG players are not able to unite as a whole solid team and in their team, there are holes that affect them a lot in Champions League. I believe one of biggest weaknesses of PSG is their coach position and they must find a coach who is winner in Champions League like Ancelotti and Mourinho. They have many good attacking players so they don't need to have a coach like Pep or Klopp. They must find a coach who can bring balance for their team by improving their defense.
I also admit that the coach is one of the reasons why PSG are not very convincing when opponents are at the level of Bayern Munich, so if they are the reason why PSG never won the Champions League then they might really have to sign a coach of the class of Guardiola or Klopp. But wait, let's see how the second leg will be. I hope there is something reliable from PSG.