This still does not make sense to me. We could say that 3 subs is also unfair because RM has WC subs available while Eibar hasn't got none. This number looks like arbitrary to me, but I will not discuss it further even if I don't get the point.
Which subs would like to see? I would get Silva out, I don't recall him doing anything useful. And Casillas almost screwed up, glad he performed a good save later.
Ukraine with a clear shot on goal, but again the shot is aimed directly at Casillas. 1-0 isn't enough for Spain here, Ukraine has had enough chances to be level, if not more.