The side from the Cape Winelands join Black Leopards and the side that finishes 15th in the Absa Premiership in the PSL’s Promotion/Relegation Play-Offs, where the winner of the round-robin competition will take their place in the top-flight next season.
Veteran Senegalese striker Mame Niang converted a penalty for Stellenbosch to seal third spot in the division.
They leap-frogged AmaZulu into third after the latter lost 1-0 at FC Cape Town, a result that also saved their hosts from relegation.
Those points moved FC Cape Town out of the relegation zone with Magesi FC, who were 3-0 losers at Mbombela United, relegated to the ABC Motsepe League along with Santos.
Thanda Royal Zulu, who have already been promoted as NFD winners, beat Real Kings 2-1, while Royal Eagles beat Witbank Spiurs 3-1. Black Leopards lost 3-0 at home to Mthatha Bucks.