Mario Gotze is not exactly looking forward to his return to Dortmund this weekend.

German international midfielder Gotze and his Bayern Munich team visit the Westfalenstadion to face his old team Borussia Dortmund on Saturday, and he is sure to get a fiery reception.

Former Dortmund golden boy Gotze shocked the club to the core towards the end of last season, when he agreed to join their Bundesliga rivals Bayern in a €37 million deal.

He had grown through the ranks at Dortmund, and was the player Jurgen Klopp had built his swashbuckling team around.

It was considered a traitor’s act when Gotze quit Dortmund for the team who were in the process of taking their domestic crown, and who then beat them in the Champions League final with him injured in the stands.

And so Gotze knows he faces a mental test when he takes to the field for Bayern at his former stomping ground.

"This will be one of the most difficult moments in my career," he told kicker.

"But ultimately I have to cope with it, because it was my decision."

The match could have major implications in the Bundesliga race, with Bayern threatening to run away with proceedings having mustered a four-point lead at the top of the table.

And Dortmund’s president, Reinhard Rauball, has painted the clash as a seminal moment in German- and also global- football this season.

"At least, this is the most important week of the first half of the season,” Rauball told kicker.

"The result of this match is decisive for the Herbstmeisterschaft [Bundesliga leader after the first half of the season, unofficial title in Germany].

"The whole Bundesliga will be watching this match. It will also have an international resonance like the Champions League final, which has gained us worldwide recognition."