River Plate was promoted to Argentinas first division after defeating Almirante Brown 2-0 in the last round of matches to finish top of the second division on Saturday.
Former France international David Trezeguet scored the second-half goals, both of which were set up by halftime substitute Rogelio Funes Mori.
River Plate has won the Argentine first-division title a record 33 times but was relegated a year ago, sparking riots in Buenos Aires by angry fans.
Trezeguet opened the scoring four minutes after halftime, running onto a pass from Funes Mori and striking a left-foot shot from the left edge of the penalty area inside the far post.
Almirante Brown players complained to the referee that Mori was offside and TV replays showed they were correct.
Trezeguet added his second one minute from the end, with Funes Mori breaking free down the right wing and laying off a low cross for the Frenchman to tap in.
River's promotion means the derby against Boca Juniors - one of world football's most famous rivalries - will resume next season.
One of the stands in River's Monumental Stadium was empty due to the death of a fan during the game between River and Boca Unidos two weeks ago.
Quilmes was the other automatically promoted club after it won 2-0 against Guillermo Brown.
