Van 't Schip slams City shocker
The visitors were outclassed in the middle, looked disinterested and slow in defence and their finishing up front was abysmal.
When City conceded three first-half goals in the space of 14 minutes, their fate was effectively sealed.
"We were not in the game at all the first half-hour," van 't Schip said.
"Before we knew it we were 3-0 behind.
"All the things we said before the game that we should try to avoid actually happened.
"We didn't keep the ball two times (consecutively) passing to each other.
"If you have players who are having an off day or not defending as you should expect, then it becomes difficult."
Melbourne's horror night took a turn for the worse in the 66th minute when - shortly after Aaron Mooy saved some face with a nice penalty goal - Dutch defender Kew Jaliens, who had just returned from suspension, was red-carded for a clumsy shove of Craig Goodwin.
Jaliens will miss this weekend's elimination final which will be against either the Reds for the second week in a row, or against Wellington Phoenix if the New Zealanders lose to Sydney FC today.
Whoever the opponent, van 't Schip knows a vast improvement will be required in order for City to avoid being finals fodder.
"We have to make sure we are ready for it," he said.
"It doesn't matter if we play Wellington or Adelaide. If we're up to it, we can play well against both teams.
"We have to repair it ourselves and make sure this week whoever the opponent's going to be, Wellington or Adelaide, that we're up for it."
If there was a small silver lining in Saturday's big defeat it was the fact City would remain locked in for fifth spot on the ladder, win, lose or draw.
The result was largely irrelevant, although performance itself, on the eve of finals, was a concern.
"If you have to lose, better to lose now in what was a game that wasn't that important for the points and ranking," van 't Schip said.
"But of course it has importance in the mental aspect.
"We have to bounce back, prepare ourselves and get mentally ready for this week because that's what we've worked for the whole year."