Manchester City manager Manuel Pellegrini faces a lengthy Uefa ban after questioning referee Jonas Eriksson's impartiality following Barcelona's 2-0 Champions League win at the Etihad Stadium.
Lionel Messi's successful penalty, which followed Martin Demichelis subsequent sending off, and Dani Alves' stoppage time goal gives Barca a healthy advantage to take into the second leg of the last 16 tie at the Nou Camp in three weeks time.
But Pellegrini was fuming with the decision to not award City a foul for an incident involving Jesus Navas before Demichelis' tackle, while the Chilean boss also claims that the challenge which saw the centre back foul Messi took place outside the penalty area.
Replays have proved inconclusive but Pellegrini has risked a stadium ban from Uefa after calling into question the allegiance of Swedish official Eriksson who the City boss believes was making up for previous decisions against Barcelona.
"I think that the referee decided the game," Pellegrini said. "Before the penalty there was a foul on Navas when he [the referee] was three meters away from the play so he saw it without any problem.
"But from the beginning I felt that the referee was not impartial to both teams so he decide the game with that foul that he didn't whistle and the penalty of Demichelis that was not a penalty because it was outside the box. Playing 40 minutes with one player less is very difficult against Barcelona.
"He did not have any control of the game yet I do not think it was a good idea to put a referee from Sweden in charge of such an important match and a referee who made important decisions against Barcelona."
The comments relate to the Champions League quarter final in 2012 between AC Milan and Barcelona in which Eriksson officiated and saw the official reject a number of penalty appeals during a goalless draw at the San Siro.
"The contact was outside the box, that is the foul you can not continue the foul," Pellegrini continued.
"The more important mistake is the foul against Navas. It was the not the only one from the beginning and that is why the game is difficult to analyse because before the penalty Barcelona had chances. It is disappointing because that important action decided the game.
"There is more important football in Europe than in Sweden. A big game with two important teams I think that kind of game needs a referee with more experience. But I repeat I think the mistake was to put in a referee who damaged Barcelona.
"This group referee against Milan and he made an important error against Barcelona."
Arsenal manager Arsene Wenger was banned for three matches for criticising officials in 2012 and despite the Frenchman having incurred previous punishments, Pellegrini can expect a similar if not longer ban for his outburst.
Though City appear likely to exit the Champions League following the disappointing first leg defeat to Barcelona, any prospective ban would roll over for the start of next season's campaign.