In 1971 Guidi became manager and Lanús started a new season in Primera B. The team made a great campaign winning a new title in second division and therefore promoting to Primera División. Lanús played a total of 28 games, winning 17 with 4 losses. The squad scored 68 goals and received 31. Unfortunately for the club, the tenure of Lanús on 1972 Primera División season was the worst in its history, being relegated again at the end of the championship.