Bruno Pitton on Saturday gave the visitors an early lead at the Libertadores stadium but Independiente equalised when Yeimar Gomez turned the ball into his own net just before halftime, reports Xinhua news agency.
The result lifted Independiente to seventh in the standings and kept alive their hopes of a top four finish, which would earn them a place in the 2020 Copa Libertadores.
Union dropped to ninth, four points behind Independiente and 18 points adrift of leaders Racing Club.
In other matches on Saturday, Estudiantes secured a 1-0 home win over Patronato and Talleres de Cordoba held Atletico Tucuman to a goalless draw.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)