Yaya(and god knows this hurts to write) is killing this team(the cup team) in the same way Clichy was. He's not just having a poor game, he's causing everyone around him to have poor games.
Case in point, Mangala receiving the ball on the touchline from Bravo. It's a hospital pass. It's lead to frantic scenes as Mangala isn't good enough to comfortably play it out from there.
BUT, he should never have to. If you watch Ederson with a centre back and Fernandinho, Dinho moves into space to allow the ball to be received once the presser steps up to attack Mangala(or whoever is in that position). It is never an issue with them. But Yaya doesn't move in between the press and that means the press works. Bravo can't put the ball where it should be going and he gives a terrible ball to Mangala who is on the by-line with a press approaching him. The next move is for him to play it to the left back, who looks for the midfielder. Yet again, Yaya is walking and not where he should be, meaning ZInchenko either has to try play out, hoof it, or give it back to Mangala.
This simple little sequence gave us nightmares yesterday, purely because Yaya didn't play his part in the move.
I love Yaya. I wanted him to stay. Build him a statue, make him a coach. But for the sake of those in the team, don't play him anymore.