Gundogan, 28, was treated to thunderous applause and standing ovations by home fans after he helped orchestrate Germany's 8-0 demolition of Estonia in Tuesday night's Euro 2020 qualifier in Mainz.
It was a far cry from a year ago, when Gundogan was booed and whistled by German fans during a pre-World Cup friendly against Saudi Arabia in Leverkusen after he and team mate Mesut Ozil had appeared in a photograph alongside Turkish president Recep Tayyip Erdogan in May 2018.
The political fallout from the photograph overshadowed Germany's disastrous World Cup campaign and eventually led Ozil to retire from international duty, accusing German football officials of racism.
Gundogan, who like Ozil refused to apologise for the controversial photograph, said that the cheers in Mainz on Tuesday, when he came off after converting a first-half penalty, had helped to heal the wounds of 2018.
"It is really nice and it does me a lot of good, especially after the negative times last summer," he told reporters after the game.
"It wasn't just me -- we all had a very difficult time of it for Germany."
Other senior players such as Thomas Mueller, Jerome Boateng and Mats Hummels have been dropped from the national team set-up to make way for the new generation since the World Cup debacle.
Yet coach Joachim Loew has remained loyal to Gundogan, who showed his class with a superb performance against minnows Estonia.
The midfielder said he remained "proud" to represent Germany, and that the young team hoped to challenge for titles in the coming years.
"Now it is fun again, both on the pitch and in the stands. It makes us want more."