The Italian was shown the door by Roman Abramovich just hours after Chelsea were beaten 3-0 by Juventus to leave their Champions League hopes hanging by a thread.
Rafael Benitez has been hired as the 42-year-old’s replacement until at least the end of the season.
Former midfielder Di Matteo has hailed last season’s European triumph with Chelsea as the greatest achievement of his career.
In a statement released via the League Managers Association, Di Matteo said: “It was an honour for me to be appointed manager of a club that I loved playing for and one that is so close to my heart.
“I am extremely proud of the successes and trophies that we were able to bring to the club in recent months.
“Lifting Chelsea’s first Champions League trophy, in Munich, was the best achievement in club history and without doubt the highlight of my career to date, both as a player and manager.
“It is a memory I will treasure for the rest of my life.”