After losing 2-0 at the Etihad in the Champions League last 16 first leg match Manuel Pellegrini attacked the referee.
The City manager said: "From the beginning I felt the referee was not impartial to both teams so he decided the game with a foul that he didn't whistle against and a penalty with Demichelis that was not a penalty, it was outside the box.
"He did not have any control of the game. He was on the side of Barcelona from the beginning until the end.
"I think it was not a good idea to put a referee from Sweden in charge of such an important match, especially a referee who has made an important mistake against Barcelona in a previous match."
FIFA's referees chief has come to the defence of Swedish official after he was accused by Manuel Pellegrini of favouring Barcelona.
Pellegrini accepts his side face a tough task against Catalans in their Champions League last-16 tie, but he is far from intimidated.
Manchester City host Barcelona in the first leg of their Champions League last-16 tie. Here is a look at some of the likely key battles.