After Orlando Pirates dominated the early exchanges, they were caught off guard when Ashley Cupido sent a long ball to Devin Titus who beat Sipho Chaine to claim the lead for Stellenbosch in the 33rd minute.
It was the all-important goal of the afternoon as Stellenbosch won 1-0 to end the Buccaneers' run of seven successive PSL victories.
The result saw Pirates remain second and failing to go back on top of the table where Mamelodi Sundowns are settled with 21 points, the same as the Soweto giants who have an inferior goal difference.
Having collected maximum points, Stellenbosch jumped from position five to third on the log.