Luckily you're not the manager.
Having equalised, it was also important not to lose, so bringing on a DM was sensible, as Yaya was doing it alone at that point. It also allowed the opportunity to let him get forward a bit more, and he does bring a goal threat.
Fernando has been one of our better players over the last few weeks, most have recognised that, obviously you're not one of them.
Also Silva was having a pretty poor game, most seem to have recognised that too, in fact he was lucky he had been replaced already in my view.