Nigeria striker Desire Oparanozie scored the only goal against a disciplined South Africa to earn her side a place in the final of the African Women's Cup of Nations against Cameroon.
South Africa started brightly but the Desiree Ellis-led side failed to capitalise on their early dominance.
Oparanozie and Ngozi Okobi both had chances to put seven-time champions Nigeria ahead in the 25th minute, but goalkeeper Andile Dlamini thwarted their shots.
Seven minutes later, South Africa had the ball in the net but it was ruled out for offside.
However, Oparanozie put Nigeria ahead with a powerful free-kick eight minutes after the restart.
Faith Ikidi was fouled in front of the South Africa box and the Guingamp forward blasted the resulting free-kick past the Banyana Banyana wall.
Wounded South Africa pressed and pushed for an equaliser forcing Nigeria to defend stoutly.
The Super Falcons almost conceded a bizarre own goal in the 83rd minute, but goalkeeper Alaba Jonathan was alert to save Ugo Njoku's awkward header on the line.
Banyana piled on the pressure and had two late chances cleared off the line, but Nigeria held on to set up a third final between Cameroon in the African Women's Cup of Nations.
The Indomitable Lionesses lost 5-0 to continental powerhouse the Super Falcons in 2004 in South Africa, while Nigeria produced a tactical performance to beat Cameroon 2-0 in the 2014 edition in Namibia.