"It was something special for me to play against my old friends," he told the Bundesliga champions' website. "It was a good return for me, a great game from us.
"Most important are the three points. The key to the victory was our respect of Roma - coach Pep Guardiola rightly told us before the game that they are a top team with plenty of quality.
"Though I am very satisfied with the win, but at the same time it's bittersweet because they're my old friends. The club and the city are in my heart.