He is under immense pressure, from a sub and underdog, to a main man spearheading the team into 3 finals. Underdog, wildcard, 2nd man is easy, it's being the everyone's hope pressure that is hard, even Lewandowski after all these years seems to have trouble with it at times.
That excluding the attention he will get now. Ancelotti doesn't do tactics, but Inzaghi does.
I will say the same thing I say about Lewandowski - there are many factors to a bad game - he had good games as a starter, Flick knows what he's doing etc etc. Only problem being, there's not a lot of time left for Flick to test and decide (as even injured Lewandowski might not be completly off the cards) so Ferran better step up soon.