Argentinos Juniors continued its unimpressive start to the Clausura season with a third straight defeat at the hands of visiting Arsenal Sarandi.
The game was goalless until Julio Cesar Furch netted in the 66th minute, with Sarandi's second following three minutes later through Carlos Carbonero.
Leandro Barrera got a consolation for Argentinos with four minutes remaining.
San Lorenzo drew 1-1 at Estudiantes in the other fixture, giving the home side a first point of the campaign.
Duvan Zapata put Estudiantes in front after seven minutes, Santiago Gentiletti grabbing the equaliser 11 minutes from time.