Velez Sarsfield missed the chance to go clear at the top of the Clausura table after they were held to a goalless home draw by 10-man Lanus.
The defending champions joined a four-way tie at the top after they failed to break down lowly Lanus, who had Mario Regueiro sent off on 81 minutes.
Boca Juniors and Newell's Old Boys can pull away from Velez at the top when they play tomorrow while the other team locked on 20 points is Tigre.
Colon moved up to sixth as Esteban Fuertes scored the only goal of their 1-0 win over Argentinos Juniors on 33 minutes.
Estudiantes slipped up 3-2 at Atletico Rafaela who grabbed control thanks to early goals from Oscar Carniello (15) and Matias Fissore (20).
Mauro Boselli pulled one back on the stroke of half-time but a 56th-minute Dario Gandin penalty gave Atletico the breathing space to allow Duvan Zapata to reply six minutes later.
Racing Club beat nine-man San Martin San Juan 1-0 thanks to an 84th-minute goal from substitute Pablo Caballero.
San Martin San Juan had Raul Saavedra sent off on 64 minutes and he was followed by Maximiliano Bustos a minute after the goal.
