Jose Mourinho believes there is a campaign to influence referees' decisions against his Chelsea side.
Mourinho was angry at referee Anthony Taylor for not awarding a penalty during the 1-1 draw at Southampton.
Midfielder Cesc Fabregas was booked for diving after going down in the area under Matt Targett's challenge.
After the game Mourinho told BBC Sport: "The media, commentators, other managers are all doing it [putting pressure on referees]."
In his news conference later, he added: "There is a campaign against Chelsea. I don't know why there is this campaign and I do not care.
"Everybody knows it was a penalty. The referee made a mistake, people make mistakes and he made a big mistake. He is a good referee and a good guy, he is young, he has years and years of football ahead of him but it is a big mistake."
Referee Taylor deemed Fabregas to have taken a dive under pressure from Targett, but there appeared to be contact from the 19-year-old full-back.
Fabregas, who protested against the decision, said: "There was definitely contact, the referee didn't have the best game of his life and I don't think he will sleep that well tonight, he had an awful game."
|BBC pundit Garth Crooks on Final Score:|
|"Here we see a classic case where Cesc Fabregas is in the box and genuinely gets tripped. I wonder if what has happened over recent weeks means the referee isn't interested? It is a stonewall penalty."I have watched a lot of Chelsea and they get a lot of calls that go their way. They have had a lot of controversy with diving recently. What goes around, comes around. They have to take it."|
His manager Mourinho said recent pressure from managers on referees in the media led to the Blues not being awarded a penalty shortly after the break at St Mary's Stadium.
West Ham manager Sam Allardyce accused Branislav Ivanovic of going down "looking for a penalty" in the Blues' 2-0 victory on Friday.
And Mourinho said: "After the game against West Ham, Sam is speaking about Branislav Ivanovic [diving], what is this? Then, you come here [Southampton] and you have a crucial decision and the referee makes the wrong decision. He made a mistake. He assumed it.
"Out of nothing, Allardyce starts speaking about Chelsea players diving, then another coach and another coach. The referee changes a penalty for a yellow card.
"[The] same happened with Diego Costa in the game against Burnley. That I can't understand. The reality is there are penalties and penalties - this one was a huge one. Match after match coaches are telling Chelsea players are diving. I will go to the referee and wish him a good year and tell him he will be ashamed."