Hans-Joachim Watzke says Borussia Dortmund and Bayern Munich will never be friendly, despite improvements in the Bundesliga rivals' relationship in recent years.
Mats Hummels became the latest Dortmund star to opt to leave for Bayern earlier this month, with the BVB captain playing his last game for the club against his future employers in Saturday's DFB-Pokal final.
The likes of Mario Gotze and Robert Lewandowski have also swapped Signal Iduna Park for the Allianz Arena since 2013.
Speaking ahead of Saturday's showdown in Berlin, Watzke told Sport1: "The relationship between Dortmund and Bayern has not been this good for quite some time, but it is not a friendship and nor will it ever be friendship.
"Our relationship is all about mutual respect. It's not like our relationship is unpleasant.
"There is always a chance there could be conflicts again and we will be arguing over things again. But I hope things stay as they are right now.
"Hummels' transfer was completed in a serious and respectful manner."
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