Chelsea have missed their captain's leadership and defensive ability during his suspension and Di Matteo admitted they were stronger with him than without.
He said: "He's still a fantastic defender and he's very influential when he plays, and he's used to those kinds of games as well, big pressure game and big European nights.
"Certainly, he marks his influence on the pitch and on the opposition.
"We have a good dressing room in the sense that we have a few people that are influential and they're used to these kinds of pressure games and can perform under it as well.
"JT is one but we've got others as well, like Petr Cech and others that are now coming through."