This game against Galatasaray can be compared a bit with the game against Villareal in the knockouts when Bayern Munich got eliminated because they obviously didn't take the game seriously enough. But despite the issues that Bayern displays in some of the game, I am sure that they will not underestimate Galatasaray as this is not some unknown team that nobody knows anything about. I think it is already sufficient information that Galatasaray was able to beat Manchester United at Old Trafford and Bayern Munich had their own problems to beat Manchester United at the Allianz Arena. But in this game I don't think Bayern will score many goals and win the game with only medium effort. Galatasaray will try to push them against the wall and nonstop interfere with their ball possession strategy.
It is impossible for Tuchel to underestimate this match because after all, Galatasaray is a tough opponent for them, so the slightest mistake could lead Bayern Munich to defeat. Bayern Munich will definitely not waste the opportunity to get full points in the group phase and I am quite sure they will play with a core squad to avoid defeat. Galatasaray also has experienced strikers in the team so Bayern Munich must be quite wary of them.
Bayern Munich did not play in their best condition when facing Manchester United because even though they were playing at home to Bayern Munich, Manchester United managed to score three goals and Tuchel had to prepare a solid defense in this match to stop Galatasaray's attacks.
The game is essentially over and it was a game that was very Bayern like. In this one Galatasaray had the chances so often and for such a long time to take the lead because they were the superior team for like 60 minutes in the game. They had so many more shots than Bayern and they also had really massive chances to score, but they failed. And this is what Bayern is waiting for. Let the opponent work hard without being successful, then the opponent becomes tired towards the end and then they score some easy goals. Kane has had a bit of luck, which is unlucky for Galatasaray, and Musiala's goal didn't really look too tough because the defense of Galatasaray was showing signs of being tired and also disillusioned after the Kane goal.