The home side claimed a 1-0 victory, with Silvio Romero on target in the 36th minute.
Quilmes moved to six points with a 3-0 away win at Union Santa Fe.
Jacobo Mansilla (7) and Fernando Elizari (41) did the damage before a last-gasp third from substitute Sebastian Romero.
All Boys claimed their first win of the season, 2-0 over visiting Boca Juniors.
Oscar Ahumada opened the scoring in the 52nd minute and Angel Vildozo secured the points with a 61st-minute penalty.