The Highlanders have managed just one win in their last seven fixtures and remain fourth on the table, only a point above Jamshedpur and three points above ATK.
"I find it unbelievable when you say we lost track. We lost only two times this season. Same like Jamshedpur who had a lot of draws. There is also something in football called a certain quality. The depth of your squad. We played good football against Bengaluru and Delhi. If you are off track, then you don't create those chances," Schattorie said.
"All those games that we drew, there was an issue where we could not play with our strongest possible XI. That is an issue we are facing. I lost Mislav Komorski for the rest of the season."
"In the last game, ATK against Pune, they take out one midfielder and put Eugene. The depth of our squad is not on that level and that has an influence. We created a lot of chances, we need a lot more luck. We have to do with the players that are available."
Wednesday's opponents Mumbai City lost their last two matches and the former United SC coach feels their overall game is predictable.
"Last two games, they missed their main striker and then their main winger. They had an influence on their game. Their game, overall, is very predictable. I know exactly where their strengths and weaknesses are. That could be an advantage for us.
"At the same time, we have our problems to deal with. It is going to be a difficult game for sure and like every game, I am going to go for three points and take one step towards qualification."
Schattorie also identified the foreign players of Mumbai City as the key players. "I don't think you have to be a football professor to understand certain dynamics in football. The speed from the two strikers, from the centre and from the right. And the threat from the left side is (Rafael Bastos) who has a good pass behind and same (threat) for Machado.
"Those are very predictable patterns and to eliminate them is not always easy. It is the same thing when you say you know exactly what Messi is going to do, how are you going to eliminate it? I have certain ideas but its not so easy to execute it."
With three matches left, NorthEast United are in for a difficult fight for the playoffs.
"It is all or nothing. I told my players, the phase you are going into now is a phase that is done within a second. Your mindset needs to be completely different from that at the beginning of the season. You cannot afford to make mistakes, especially at this stage because now Jamshedpur is very close and ATK a little bit away. How to win is not important, we need three points. We are still doing the football part, hopefully, we can convert it into results."