The Spaniard has also hit out at the negativity from some fans following Wednesday's FA Cup fifth-round win at Middlesbrough.
Benitez has faced plenty of resistance from supporters since he joined the Blues in November on a short-term deal until the summer.
"I'm disappointed with some fans. They have to support the team instead of wasting time making banners," he told reporters.
"They have to support the team. They gave me the title of interim manager which is a massive mistake. I am the manager and I will manage this club. The fans are not helping us.
"I am a professional and I will do my job. At the end of the season I will leave."
Chelsea are currently in fourth place in the Premier League table.