Rafael Benitez has said he will leave Chelsea in May and described the decision to give him the title "interim manager" as a "massive mistake".
After beating Middlesbrough 2-0 in the FA Cup fifth round, the Spaniard also criticised some of the club's fans.
He said: "Chelsea gave me the title of interim manager, which is a massive mistake. I'm the manager.
"The fans are not helping us. At the end of the season I will leave. They don't have to worry about me."
Benitez's defiant post-match interview came after the former Liverpool manager was once again targeted by a section of his club's own supporters.
The 52-year-old has always been unpopular with some Blues fans since he took over from Champions League-winning manager Roberto Di Matteo in November.
A section of the club's supporters were unable to forgive or forget some of the comments Benitez made while in charge of Liverpool during the Champions League encounters with Jose Mourinho's Chelsea.
"A group of fans, they are not doing any favours for the team when they are singing and wasting time preparing banners," he said after the victory at the Riverside.
"They have to concentrate on supporting the team, that's what they have to do.
"Every game they continue singing and preparing banners, they are wasting time. What they have to do is support the team.
"I am a professional and I am doing my job. What I want to do is win every single game for Chelsea."
Reports emerged from Stamford Bridge earlier in the week that Benitez was involved in a heated exchange with members of his squad after their 2-0 defeat at Manchester City on Sunday.
Before the FA Cup tie with Middlesbrough, Benitez insisted he had a "fantastic" relationship with the club's players.
He reiterated his satisfaction with his players after they set up a FA Cup quarter-final clash with Manchester United.
"I have a top side and a good group of players who work hard and it is a top club, it is not a problem," he said.
"The problem is a group of people who can say what they want."