At the same time, Kremer, the boss, wanted to interfere all the time. Convinced of his own infallibility, he insisted on having a say in building and selecting the team. Weisweiler could not implement his concept and initially moved across the Rhine, to Viktoria Köln.
When he failed there to break the dominance of 1. FC Köln, he took over at then Regionalliga side Borussia Mönchengladbach on 27 April 1964. The rest is history. In eleven years on the Lower Rhine he turned a second-tier side into a European power, crowned by the league titles of 1969/70, 1970/71 and 1974/75, the legendary cup win against 1. FC Köln on 23 June 1973 and the UEFA Cup triumph in 1975.