Manchester City manager Manuel Pellegrini apologised on Friday for his virulent verbal attack on the match referee following his side's 2-0 loss to Barcelona in the Champions League.
Pellegrini was incensed by referee Jonas Eriksson's performance in Tuesday's last 16 first-leg match at the Etihad Stadium, which saw Lionel Messi open the scoring from the penalty spot after Martin Demichelis had been sent off for fouling him.
Pellegrini disagreed with the decision, arguing that the foul had started outside the penalty area and that City midfielder Jesus Navas had been impeded by Serio Busquets in the build-up to the incident.
He also accused Eriksson of being "not impartial" and even suggested that he should not have been put in charge of the game because he came from Sweden.
However, addressing the media on Friday, the Chilean admitted that he had spoken out of turn.
"When you lose a game the way we lost against Barcelona, you are frustrated, you are angry," Pellegrini told a press conference. "Maybe I said some things I didn't mean, so I apologise for what I said."
He added: "Also, I want to clarify what I said. I didn't make any serious accusations to anyone; not to the referee, not to UEFA, not to anyone.
"I said the referee decided the match because he didn't give us a foul against Jesus Navas and then to the penalty, we had a player sent off in that moment. The referee decided the game. A lot of time he didn't give the foul.
"It's a difficult profession. He had a bad day, and I didn't say that he was a bad referee."
European governing body UEFA announced on Friday that it has launched an investigation into Pellegrini's comments, which could lead to disciplinary proceedings.
On his allegations of impartiality against Eriksson, Pellegrini explained: "I felt from the beginning his criteria was not the same for both teams.
"I think he had a bad day -- everyone can have a bad day -- but I didn't say that intentionally he didn't give fouls for us or did give fouls for Barcelona.
"I said from the beginning it was not the same criteria. I repeat: a bad day, not dishonest."
On his comments about Eriksson's nationality, he added: "To say because he was always refereeing in the Swedish league, and that maybe it was better for so important a game to have another kind of referee -- it is another thing I didn't think.
"It is not an offence to Sweden or the Swedish people or referees. Sweden is a country that has a lot of good players. They have one of the best in the world in Zlatan Ibrahimovic, and it can also have a good referee."