Borussia Dortmund might have beaten Cologne 5-0, but the game could be replayed after the visitors said they intend to protest following a refereeing error.

Referee Patrick Ittrich at first ruled Dortmund's second goal out for a Sokratis shove when Cologne defender Dominique Heintz collided with goalkeeper Timo Horn and the ball fell for the BVB man to poke over the line. The goal was only awarded after consultation with the video assistant, but Cologne were furious that the goal stood after VAR when Ittrich's whistle for the alleged foul came before the ball had crossed the line.

"We want to protest. It was an irregular goal in breach of the rules," Cologne's sporting director Jörg Schmadtke told Sky afterwards. "That was clearly a wrong decision which decided the game."

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Borussia Dortmund CEO Hans-Joachim Watzke added fuel to the fire by saying to Sky: "The only thing which is clear is that Cologne can't take losing."

Video assistance intervened for a second time later on when Cologne defender Lukas Klünter blocked Maximilian Philipp's header with his arm. Play continued but Ittrich called it back, booked Klünter and awarded the penalty (which Pierre-Emerick Aubameyang converted) after receiving instructions on his earpiece.