PSG are second in Group F following a shock 4-1 defeat at Newcastle United earlier this month and take on seven-time winners Milan home and away in their next two matches in the competition.
The French club have three points, behind Newcastle on four but a point ahead of Milan. Borussia Dortmund have one point.
“These are vital games [against Milan] considering the circumstances of the last two rounds but we’re concentrating on each game,” Enrique told reporters.
“The real value of AC Milan is that it’s a great team that has always played in the major competitions.
“Every club in the world has its ups and downs but AC Milan are doing well at the moment. That’s why this is the ‘Group of Death’: all four teams can go through.”
Asked how PSG would approach Wednesday’s game, Enrique said: “Attack as always, we’re a team that has always attacked.
“We’ve always had more possession than our opponents. We’ll also have to defend in our own half. I’m optimistic from what I see, from what I perceive from my players in the way they train.
“The fans appreciate this mentality of the players, they like to see the team defend in an organised way, that we press against our opponents, that we are always attacking.”
Donnarumma has been criticised by Milan’s fans since his departure but the 24-year-old said he had tried to block it out, adding: “It’s important to me to have a good relationship because I always gave my all right up until my last match.
“It’s normal for criticism to hurt me a bit. But I don’t have time to think about that, I have to stay focused on this match, which will be very difficult and emotional.
“I have to stay focused and not let emotion get the better of me. There will be a lot of emotion, and it will be a great joy to meet my old team mates.”