Di Matteo is expected to recall John Terry for this evening's Group E summit meeting on the anniversary of the match against QPR which led to his four-match domestic ban for racially abusing Anton Ferdinand.
Beyond that, it is hard to glean precisely what changes the Italian will make for the second of four huge matches in quick succession.
He picked his strongest available side for Saturday's Barclays Premier League win at Tottenham but may be tempted to shuffle his pack tonight with Sunday's top-of-the-table clash with United in mind.
But he said: "I won't think about Manchester United, only this game.
"We've got to focus on it, try to win the game and that's a big, big boost for our campaign in the Champions League."
Di Matteo will be aware of the number of matches played by the likes of Fernando Torres, David Luiz and Branislav Ivanovic this season and may decide one of them needs a break.
He added: "There are always knocks and bruises and maybe some fatigue as well considering the majority of our team have been away on international duty.
"Some of them have played two games for their country. All these things are things to think about."
Whatever side Di Matteo picks should be captained by Terry after Chelsea refused to strip him of the honour over the language he used towards Ferdinand precisely a year ago.
And in timing that could hardly be more ironic, the defender will also wear an armband bearing the slogan 'Unite Against Racism' as part of a Football Against Racism in Europe (FARE) campaign scheduled for this week.
It has become a cliche that Terry saves his best performances for when he is in the eye of a storm.
But never has he faced a bigger test of character than the aftermath of his guilty verdict in his Football Association racism case.
Di Matteo said: "I've never been concerned about picking him.
"He's been able to focus on the games and that's what the players love to do, playing football and it's good for them that they can focus on that."
He added: "What is common for players is that, even if they have family problems or some kind of issues outside in their private life, they tend to be able to focus on the football because it kind of just helps them."
Shakhtar boss Mircea Lucescu warned Chelsea his in-form side were a completely different prospect to Spurs.
"We are also different from Tottenham these days," he said.
"I believe that our team's level is higher.
"This is true of both each player's individual skill and the game organisation.
"I think that we surpass Tottenham in terms of those qualities."