Borussia Dortmund CEO Hans-Joachim Watzke has admitted his club underestimated ticket demands for their Champions League home semi-final against Real Madrid after fights broke out on Tuesday.
Dortmund host Real at their Signal Iduna Park stadium on April 24, but there was chaos when tickets finally went on sale at 0900 (0700 GMT) on Tuesday, half an hour later than planned, after some fans had queued since Sunday evening.
Brawls broke out amongst supporters waiting in queues at separate locations in Dortmund city centre as the tickets available were snapped up within an hour of going on sale, reported SID, an AFP subsidiary.
Police had organised the lines from midnight Monday after organised gangs had tried to aggressively jump in, but officers reported fights breaking out in the early hours of Tuesday morning.
"We had honestly underestimated this incredible stampede, it's our fault" admitted Watzke.
"We will learn our lessons from this and not offer a free-for-all ticket sale in future."
Watzke said Dortmund will reorganise their advance ticket sales in future so organised gangs, operating on the black market, can not profit and to avoid the chaos that left some fans empty-handed despite queuing overnight.
After some supporters began camping out 36 hours before tickets went on sale, Dortmund president Reinhard Rauball and club icon Norbert Dickel had handed out hot dogs and drinks to the queuing masses.
While things remained relatively calm outside the main office at the Dortmund stadium, police reported brawls broke out at other ticketing offices in the city centre and riot police were deployed.
Local police are critical of Dortmund's planning and a spokesman said: "Since there was no security at a few ticket agencies, officers from Dortmund police had to intervene."