Newell's Old Boys regained top spot in but missed a golden opportunity to extend their lead at the top as they were held to a 1-1 draw at Godoy Cruz.
Nacho Scocco gave Newell's an 11th minute lead and they looked to be cruising when the home side went down to ten men.
However, Mauro Obolo's 80th minute goal denied the Newell's victory and ensured things stayed tight at the top of the league.
Colon Santa Fe launched a stunning late comeback to earn a 2-2 draw at Quilmes, who were in control with first half goals from Juan Cobo and Ernesto Goni.
However, Goni gave the visitors hope with an own goal a minute from time - and the visitors made Quilmes pay a minute later with Emanuel Gigliotti's equaliser.
The mid-table clash between All Boys and River Plate finished goalless, with River Plate midfielder Leonardo Ponzio sent off at the end.
Information from the Press Association was used in this report