The London club is the defending European champion for the first time, but in the group phase it amassed just two points from three away matches.
The London club may have finished the season as European champion for the first time, but in the group phase it amassed just two points from its matches at Valencia, Genk and Bayer Leverkusen.
Danish champion Nordsjaelland will be playing its first ever home game in the competition - albeit in Copenhagen, rather than at its usual home in Farum - and with Chelsea having drawn 2-2 against Juventus in its opening match, Di Matteo expects nothing less than victory.
"Tomorrow is probably the most important game in this group stage for us," said the Italian in Monday's pre-game press conference.
"We drew our first game at home so it's important we gain points away from home. For us, it's a crucial game tomorrow. I want the team to be focused."
Despite reports that Di Matteo could opt to rest striker Fernando Torres, who has started every game so far this season, the Chelsea coach said there would not be too many alterations to the team that won 2-1 at Arsenal at the weekend.
"It'll be a strong team," he said.
"There might be a couple of changes, because we played a very intense game on Saturday. A win would certainly help, and that's what we're aiming for."
One player hoping to feature is Frank Lampard, who has started Chelsea's last two games on the bench and did not even make it onto the field against Arsenal.
Although the England midfielder has clearly lost his claim to an automatic starting berth at Stamford Bridge, Di Matteo says he cannot fault Lampard's performances.
"I've had conversations with him, as I do on a regular basis," said Di Matteo. "He's very supportive of the team when he's not in the team, and when he's in the team, he does very well.
"We're fortunate to have a very strong squad of international players. With a busy schedule, it's important to have a deep squad.
"He played magnificently last season and this season, too, so there's absolutely no concerns about him."
Victory at the Emirates Stadium galvanised Chelsea's grip on first place in the Premier League, after an impressive start to the season in which it has taken 16 points from a possible 18.
The contrast between Chelsea's star-laden squad and that of Tuesday's opponent, Nordsjaelland, could not be more stark.
The Danish minnow was only formed in 1991 following a merger of two clubs from the eastern town of Farum, and not a single member of its playing staff had previously sampled Champions League football prior to this season.
It has, nonetheless, acquired a reputation for playing expansive, possession-based football under coach Kasper Hjulmand, and impressed despite losing 2-0 at Shakhtar Donetsk in its Group E opener.
"I had the pleasure to meet Kasper at a UEFA coaching conference in Switzerland, and I had a little chat with him," said Di Matteo.
"It's a fantastic story - winning the league for the first time in their history; a young coach, trying to develop a brand of football that he likes.
"Nordsjaelland have shown how good they are. They went to Shakhtar and had the majority of possession against a good team.
"They weren't afraid to play their football and it'll be difficult for us. On paper, we probably are the favourites, but we have to show this on the pitch."