Leaders Lanus were hammered 3-0 by Huracan while a stoppage time penalty gave inconsistent River Plate a 2-1 win over San Martin-Tucuman.
San Lorenzo, who on Thursday slumped to their third straight defeat in the Libertadores Cup when they lost 1-0 at home to Paraguayan champions Libertad, held their own until 10 minutes into the second half.
Their troubles began when Jonathan Santana was sent off for a second bookable offence and Esteban Fuertes fired Colon ahead one minute later.
Gonzalo Bergessio and Jonathan Bottinelli were given straight red cards in quick succession for bad tackles before San Lorenzo defender Gaston Aguirre gave the ball away in defence and Fuertes pounced to score again
Nicolas Torres headed the third in the 84th minute.
Colon, who have 14 points from seven games, moved up to second, ahead of River Plate on goal difference and one behind Lanus.
Lanus fell behind to a sixth minute header from Gaston Esmerada at Huracan before Javier Pastore added two more in the second half.
The third goal was set up by a 60-metre run by Matias De Federico, who beat five opponents before his shot was parried by Carlos Bossio and fell to Pastore.
Colombian Radamel Falcao Garcia converted a penalty in the third minute of stoppage time to give River a 2-1 win over San Martin.
The visitors went ahead when Facundo Quiroga headed into his own goal in the second minute before Gustavo Cabral headed River level from Marcelo Gallardo's cross on the hour.
San Martin's Pablo de Muner was sent off in the 90th minute and tried to provoke the River players by pulling Gallardo's hair before he left the field.
Defending champions Boca Juniors drew 0-0 at Tigre in a match played in scorching heat.
The kickoff was brought forward for security reasons after Boca fans fought among themselves before their previous two matches.
