The 25-year-old German, who signed for £1.9m from Sevilla, was named man of the match and said: "I think I did okay in my first game for Celtic at home.
"I have been here for a week and I need time but I enjoyed it. I think I need more games to get my rhythm, to play better and learn how Celtic play."
The right-back, who has earned 17 caps with Germany, added: "It was a cup game against a smaller team and it is the same all over the world, it's not easy playing against small teams."