Bad blood was stirred in the build-up to Saturday's German Cup final between Freiburg and RB Leipzig after a row over the seemingly innocuous matter of a commemorative scarf for supporters.
Head coach Marco Rose has left Borussia Dortmund after just one year in charge, the Bundesliga runners-up said on Friday.
The midfielder was sent on just moments before the end of the Europa League final against Eintracht Frankfurt.
Hamburg have one foot back in the Bundesliga after earning a 1-0 win at Hertha Berlin in Thursday's relegation/promotion play-off, first leg thanks to a speculative strike by midfielder Ludovit Reis.