Mikel was under fire at the start of the season after a string of lacklustre performances but Di Matteo, who hs played in a similiar role for Chelsea in his playing days, insists that the Nigerian has been under-rated.
"I don't know why Mikel is underrated by the media or the fans,"Di Matteo told Chelsea's official website, "He is very rated by us in the group and it's a position where you're a bit of an unsung hero.
"Over the years he has been almost ever-present. He was very important at the back end of last season and this campaign he has started in good form"
The Italian also feels that Mikel has been overshadowed with Chelsea boasting a plethora of exciting attacking talents up front.
"You do the dirty work which is not recognised all the time because the goalscorers and more creative players get the recognition. But he is very important for our team."
"We all make mistakes in games and I don't think he gets the credit for the work he does for the team."