Again, I am not saying that Ter Stegen absolutely must play ahead of Bravo and that Bravo is absolutely shit, but I don't think it's beneficial at all for Ter Stegen to only play CL matches if it leads to that. I think it will hit his confidence and development and with the lack of match practice, you cannot expect him to do very well either. Just as shown with Iker Casillas.
Look, I am also in team Mats.
I love Mats and think that he will be our No1 in the future years.
But, in this moment, it is just not fair and it would be wrong to change anything.
There is an old football saying, something like: "You should never change anything if your team is winning"
-- you change something, you think that it would be even better, but too many times, something goes wrong. Hard to explain what, but something just too often goes wrong.
Also, imagine if Lucho gives a chance to Mats now, for no reason, and Mats makes a blunder and we play 1:1 tonight.
How to explain his decision to Bravo after that?
-- also, Bravo will lose a bit of confidence because he was benched even though he had 4 clean sheets
-- he will know, that no matter how well he will play, he will be benched by Mats
On the other hand, how will Mats feel?
-- he got a chance, and made a mistake
-- he will be under a huge pressure in the future
So, today you have:
1. Bravo, one Gk, in good form and with high confidence
-- and a team is winning
2. Mats, 2nd Gk, who knows that he has to wait and that he will get his chance
-- his confidence is also still more or less good
Then, imagine Mats' blunder in today's match:
1. Bravo will lose a confidence and will get angry
2. Mats will be low, with lower confidence and under a lot of pressure
So, the safest and the smartest move for now will be:
-- to play Bravo, and if he will play poorly, Mats will eventually in 3-4-5-10 weeks bench him, both in Liga and Cl matches
That is the only "fair" way in this moment.