Real Madrid has often come from behind but they cannot afford to take it lightly this time as this is the first time the new format has been introduced, so if they don't take it seriously then they might just get knocked out. I agree that Ancelotti should have started thinking about benching Mbappe because besides being an option, it might make Mbappe better. There are times when a player can be better when he is left on the bench because he will reflect and try to improve himself to become a starter again.
It's hard to bench a striker when you have an injured attacker, Real played this game without Vinicius, if Ancelotti had to play without Mbappe I think it would have been even more difficult. Of course Mbappe is to blame for taking responsibility for this penalty and letting the team down, but the problem is not only him, Real has problems in defense and I think this is the main problem for Real now. I think that Real is capable of reaching the playoffs, they have games left with not the most difficult opponents and they must gain points in these matches.