David Trezeguet and Leonardo Ponzio scored first-half goals as River Plate snuck past Colon, 2-1, on Sunday.
Trezeguet got the hosts off to a good start 11 minutes into the match and Ponzio added a second goal in the 33rd minute to quickly put River Plate ahead by two goals.
Emmanuel Gigliotti pulled one back for Colon in the 74th minute, but the visitors could not find an equalizer as River Plate held on to claim its fourth win in its first five league matches.
Colon, meanwhile, remains winless this season and has just two points from five matches, leaving the club second from bottom.
The result lifted River Plate to the top spot in Argentina's top flight with 12 points from five games, but the first-place position was short-lived as Lanus climbed back to the summit on Monday with a 2-1 win over Arsenal.
Also on Monday, Argentinos Juniors remained rooted to the foot of the table following its 3-1 home loss to Quilmes.
Elsewhere on Sunday in Argentina, Ruben Botta converted a penalty kick in the 29th minute to secure a 1-0 win over San Lorenzo, while Juan Eluchans and Nicolas Blandi exchanged goals as Atletico Rafaela and Boca Juniors played to a 1-1 draw.
On Saturday, Union and All Boys battled to a 1-1 stalemate, while Newell's handled Estudiantes, 4-2. Bruno Zuculini, Luciano Vietto and Rodrigo De Paul all scored as Racing topped San Martin by a 3-0 count.
Friday's action saw Martin Dario Zapata score the only goal in stoppage time of Belgrano's 1-0 victory over Velez Sarsfield, while Alexis Nicolas Castro hoisted Godoy Cruz to a 1-0 win over Independiente.