The west Londoners overcame the odds at Stamford Bridge to progress to the quarter-finals, overcoming a 3-1 first-leg defeat in Napoli to go through 5-4 on aggregate after extra-time.
"For the club, you know, it meant a lot," said interim boss Di Matteo, who ran on to the pitch to embrace the Chelsea players on the final whistle.
"To still be able to play in the Champions League, and also you could see how much it meant to the players.
"I think everybody was very happy and delighted that we managed to stay in the Champions League after putting on such a big performance tonight.
"I've had some great nights, I have to say, but I think it will probably go down in the club's history.
"To have come back from a two-goal deficit from the first leg and you saw the players tonight, how they performed.
"They showed passion, that they care about the team, the club, the supporters. We gave us a big boost going forward."
He added: "The home advantage was on our side tonight. Napoli are probably stronger at home than away from home, even though they are very dangerous with the transition.
"I think our supporters helped us win the game tonight as well and we just tried to go back to basics. We tried to be solid, not concede goals and we're always confident in the quality we have in the team to score goals ourselves. Every win will increase the confidence of the team."
Source: PA
Source: PA