Liverpool boss Jurgen Klopp explained Dominik Szoboszlai's substitution during the 0-0 draw with Manchester United.
The Hungary midfielder was changed on the hour mark for Joe Gomez.
Asked if it was a form issue, Klopp said: "No, not at all. It might have had until two or three games ago where it was slight, after the first impression he made obviously, it was always clear things will not always go like this.
"He is still a very young boy but he was exceptional today in a lot of situations in the game. Then we lost a couple of balls. It had nothing to do with the substitution or whatever.
"It's just we have options to do it and we wanted to change system and then we have to think who we want. We wanted to have Joey then higher, properly on the wing. Same for Kosti (Tsimikas).
"So you need players in these half-spaces. Cody Gakpo right, Lucho (Luis Diaz) left, Mo Salah in the centre. Then we changed again with Harvey Elliott on 10. We played on a team who played man-marking.
"Each little tweak can make a massive difference if you can use it. Actually, we were there. We were there. We had these moments where we passed the ball to the outside, if there, find an overlap. Overlap was there in moments, but then shoot the ball to the outside of the net instead of letting them make a mistake.
"If you bring that ball in the six-yard box, it's super difficult to defend because there are a lot of legs. It can be a Manchester United leg that brings the ball over the line. These were the moments where we were not really not. This was the problem."