The Italian met his demise on Wednesday after the Blues were beaten 3-0 by Juventus in the Champions League on Tuesday night which has their title defence hopes hanging by a thread.
The decision to sack Di Matteo, who led the club to the FA Cup/Champions League double last season, has been met with derision by the wider football community and has also prompted plenty of praise from around with midfield star Mata sending kind words to his now former mentor.
"It's been a difficult day," said Mata. "Roberto Di Matteo is no longer our manager," the Spaniard wrote on his Facebook page.
"I would like to thank him for all this time with us and wish him the best of luck for the future.
"As a player he has been a legend for the 'Blues'. With him as a manager we won our first Champions League.
"He will always be remembered. Good luck Robbie!"