sentences:  Their coach Hennes Weisweiler intended to strengthen the defense of his young team, which was already very strong offensively, but lacked the defensive thoroughness to succeed in a long league campaign.For the 1969–70 season, Mönchengladbach added Sieloff as sweeper as well as Ludwig Müller as the stopper.With the defense strengthened, Borussia Mönchengladbach won the 1969–70 and the 1970–71 Bundesliga seasons.