The German side will take the two-goal lead into the second leg of their quarter-final tie with the Italian team.
The 29-year-old told Sky Sports News: "When we spoke about the game before we said we cannot concede a goal today, that is the most important thing. In the end, 2-0 at home, is a good advantage.
"I think it was a very good game to watch because both teams were pressing forward and it was almost one-against-one on the whole pitch.
"I think especially there was a period in the first half straight after I came on when they made some mistakes and we were on the counter-attack and we had some good chances, myself as well. It was just a bit unfortunate that we didn't score another goal."
The second leg of the tie takes place next Wednesday.