Having been found guilty by the Football Association of racially abusing Anton Ferdinand in a Premier League game a year ago, Terry is currently serving a four-match domestic ban.
As a result, Tuesday's Group E battle with Shakhtar Donetsk offers the Chelsea skipper the perfect chance to put the events of recent weeks behind him.
Speaking to The Telegraph ahead of Tuesday's match in Ukraine, Di Matteo said of Terry's suspension: "I certainly think he has realised that he used language that was inappropriate and he has apologised for that and has certainly learned from that issue."
Shakhtar are currently 15 games unbeaten this season, with 14 of those games having yielded victory, and Di Matteo suggested that the tie in Donetsk offers Terry the ideal opportunity to underline his importance to the side.
The manager said: "With good performances and good behaviour in the future he should still be looked upon as the leader for our club. I've never been concerned about picking him."
Di Matteo also stated that Terry had the strength of mind necessary to focus on playing football, and not allow off the field issues to affect his performance in what is a crucial tie for the Stamford Bridge outfit.
"He’s been able to focus on the games and that’s what the players love to do, play football – and it’s good for them that they can focus on that."
By Chris Weatherspoon
