San Lorenzo came from behind to defeat newly-promoted Godoy Cruz 2-1 and claim their first triumph in the Apertura tournament on Saturday.
Martin Aguirre opened the scoring for Godoy Cruz before Gonzalo Bergessio equalised and substitute Juan Carlos Menseguez netted the winner.
San Lorenzo had lost their opening fixture to Tigre, who on Saturday recorded their second triumph in as many games with a 2-1 victory over Arsenal.
Midfielder Diego Castano scored twice for Tigre, while Luciano Leguizamon was on target for Arsenal.
Meanwhile, Argentinos recovered from last week's 3-0 reverse to Arsenal with a 4-1 victory over Velez Sarsfield.
Andres Scotti, Nestor Ortigoza, Juan Mercier and Gonzalo Aban were on target for the hosts with Jonathan Cristaldo hit a consolation for Velez, whose misery was compounded when defender Fernando Tobio was sent-off late on for punching Argentinos forward Gabriel Hauche.
Colon won 4-1 at Gimnasia from Jujuy with Ariel Garce, Alejandro Capurro, Pablo Aguilar and Ruben Ramirez on target.