The Blues, who became only the fourth club ever to overturn a two-goal first leg deficit when they beat Napoli to reach the quarter-finals, need only draw the second leg to avoid becoming the third side to crash out after a first-leg away win.
Complacency would therefore appear to be the biggest threat to Di Matteo's men setting up a mouthwatering tie against Barcelona or AC Milan, and he cautioned: "It is a danger. This is half-time and we're leading 1-0. But a 1-0 lead is basically nothing."
Chelsea are odds-on favourites to reach their sixth semi-final in nine years, having sealed a surprisingly straightforward 1-0 victory in last Tuesday's game in Lisbon, but Di Matteo insisted: "We'll have to go into this game with the right attitude, the same attitude as against Napoli.
"Nothing has been done yet. We're aware of that. We need to go and qualify for the next round," he added.
Benfica's limp performance at the Estadio da Luz contrasted sharply with those in their Champions League campaign as a whole, with Jorge Jesus's men having helped eliminate Manchester United in the group stage.
Di Matteo added: "This tie is far from over. They have scored in every away game of their Champions League season, so it's a difficult task."
The match will mark a month since the Italian succeeded the sacked Andre Villas-Boas, four-and-a-half weeks that have witnessed an incredible turnaround in Chelsea's fortunes.
But Di Matteo continued to snub questions about his own future and asked why he was so reluctant to declare he wanted to manage such a fantastic club full-time, he said: "It's a fantastic club, I'll agree with you on that.
"I need to win games, it's as simple as that. It's a results business and that's all that matters."
Source: PA
Source: PA