The European champions have stormed to the top of the Barclays Premier League this season with a scintillating new brand of attacking football.
But they are not quite the finished article, a stark reminder of which came during what was their first major setback of the season in Tuesday night's Champions League defeat at Shakhtar Donetsk.
And, with John Terry and Frank Lampard both missing for the clash at Stamford Bridge and the following two games through suspension and injury, the coming days will provide the biggest insight yet into how able Chelsea's new guard are to cope without two of their most talismanic figures.
"We've had a good start, but we need to show consistency over a long period of time," said Di Matteo, whose side are four points clear at the top of the table.
"We have a busy fixture list now coming up.
"So, it will be a test for us, a challenge for us, and it will also test the depth of our squad.
"The players that have come in have settled in quickly and that's been a big bonus for us, and I think thanks to the support as well from the club and from all the other team members that we already had here."
Di Matteo has so far succeeded where so many before him have failed by managing a successful transition between the blueprint first established under Jose Mourinho to something more akin to the style favoured by Barcelona.
The Italian was coy about whether United would be facing the most attractive Chelsea side of the Roman Abramovich era.
"I'll leave that up to you to decide whether it is or not," said the Italian, refusing to reveal whether his revolution was meeting with the approval of Abramovich, who has long demanded more flair in the team.
"Our belief is that, with the players that we have, it's our best chance to win games, playing like this."
Chelsea have tried many times to do so in the past, but without the kind of personnel required, something they have addressed in dramatic fashion by splashing out £130million on their front four.
Di Matteo said: "As a manager, you need to be able to adapt to the players that you have at your disposal.
"Because there's no point, in my opinion, playing something that your players aren't comfortable with or don't have the characteristics for it.
"Of course, we wanted to maybe change a little bit the way we played last season or over the years. Certainly, that was the idea.
"That's the club's idea here, everybody's idea here."
Di Matteo has repeatedly spoken of the importance of finding the "balance" between attack and defence and acknowledged that was still a work in progress.
"As a team, we obviously still have to improve on that," he said.
"We need to work on our defensive responsibilities and discipline and balance.
"It's going to take time, for sure.
"And we have shown and proven that we can do it because, many games, it's been done very well, and we'll continue to do so and work on it and improve."
That involves the likes of much-vaunted attacking trio Juan Mata, Eden Hazard and Oscar doing their share of the spade work.
"I think their willingness is very important to do it and they have it," Di Matteo said.
"So, I'm sure we'll come to that point."
The Chelsea boss insisted it was also not the right time to be talking about the effect of the game on the title race.
"It's still a little bit early in the season, I would say, for a game like this to be decisive," he said.
"They're a great competitor of ours and we're playing at home and so we want to try to keep our home record very good and have a good game and keep the distance from them."
The match will, however, have an impact one way or the other on the ongoing fallout from Terry's racist abuse of Anton Ferdinand.
Ferdinand's brother, Rio, and Ashley Cole are not expected to snub each other during the pre-match handshake, while Terry himself will pledge his support to the 'Kick It Out' campaign in his programme notes, as is customary