Colon missed the chance to join Boca Juniors at the top of the Apertura standings as they were held to a goalless draw at home by San Martin.
The hosts were not without their chances but their opponents proved stubborn in
defence, with the result leaving Colon two points behind the leaders, who also have a game in hand.
Banfield continue to prop up the standings following a 1-1 draw with Olimpo, who took the lead after 26 minutes through Martin Rolle.
Substitute Maximiliano Laso then equalised 10 minutes into the second half to leave Banfield with four points from eight matches.
In today's other fixture, Juan Ferreyra's double earned All Boys a 2-1 victory at Arsenal.
Ferreyra found the mark after 19 and 35 minutes, the second coming from the penalty spot, with Lisandro Lopez's 90th-minute strike coming too late to save the home side.
