In the next season, 1964–65, the club signed the youngsters, Jupp Heynckes and Bernd Rupp, and some of the youth team joined the professional squad. Their average age of 21.5 years was the lowest of all regional league teams. They earned the nickname "foals" due to their low average age as well as their carefree and successful play. Reporter Wilhelm August Hurtmanns coined the nickname in his articles in the "Rheinische Post". He was taken with the style of Borussia and wrote that they would play like young foals. By April 1965, the team had won the Regionalliga West and thus secured the participation in the Bundesliga promotion round in Group 1. This saw the team play against the competitors of Wormatia Worms (Second in the Regionalliga Südwest), SSV Reutlingen (Second in the Regionalliga Süd) and Holstein Kiel (Champions in the Regionalliga Nord) in first and second matches. Of the six games Borussia won three (5–1 in Worms, 1–0 against Kiel and 7–0 against Reutlingen). The achievement of the first place made promotion to the Bundesliga safe. Together with Borussia Bayern Munich rose by winning Group 2.