Dortmund notched their biggest ever away win in the Champions League in their opening group match, setting a marker ahead of their match against reigning champions Real Madrid later this month.
Goetze had left Dortmund in 2013 in even more controversial fashion, with his move announced -- the most expensive for a German player at the time with 35 million euros -- only weeks before they met Bayern in the Champions League final.
His transfer to their bitter German rivals had sparked fury among fans who had accused him of betraying the Ruhr valley club he had played for since childhood.
Goetze's return this summer was an equally heated affair with some fans angered by club bosses who welcomed him back with open arms.
But few will now think it was a bad decision after his dazzling performance on Wednesday, with the player unable to suppress his smile.
"I feel great and looking forward to what lies ahead, you can see it on the pitch that I feel good," he told reporters. "It was really fun being out there and we can really be satisfied."
Once regarded as the most talented German player of his generation, the attacking midfielder was assured a place in the history books when he scored the winning goal in the 2014 World Cup final for Germany.
But that was also the last of his major career highlights, having failed to settled at Bayern with both coach Pep Guardiola and his successor Carlo Ancelotti refusing to guarantee him playing time.
His return to Dortmund was a surprise for many but Goetze brushed off his past few seasons with yet another smile.
"What corner?," he said when asked if he had finally turned the corner. "This was a goal for the team, the club and the Champions League."
The creative player was deployed by Dortmund coach Thomas Tuchel in his more natural position behind the forwards and it paid off.
A constant source of problems for the Polish defence, Goetze upped the pace when needed, drew players on him and got on the scoresheet in an overall outstanding performance.
"One can see that things are now working out for him," said Dortmund sports director Michael Zorc. "His lightness, his ease is coming back again. Of course there was never any doubt about his football skills."
(Editing by Amlan Chakraborty)
