San Lorenzo retained their top-flight status on Sunday evening after a 1-1 draw with Instituto gave them a 3-1 aggregate triumph in their promotion/relegation play-off.
The hosts' 2-0 victory in the first leg put them in control and they completed the job at the Nuevo Gasometro stadium.
Diego Lagos hinted at a comeback when he put Instituto, who finished third in the Primera B Nacional, ahead after 69 minutes but Nestor Ortigoza's spot-kick nine minutes later proved enough for San Lorenzo.
San Martin San Juan also kept their place in the top division with a goalless draw against Rosario Central.
The first leg was also goalless, but Rosario as challengers needed to win the tie, with a draw enough to ensure San Martin will take their place in next season's Apertura.