The game looked destined for a goalless draw when Given Msimango put the ball past his own goalkeeper two minutes from time to hand Stellies the victory that took them to 29 points, two clear of Orlando Pirates in third position.
The Rockets closed 2021 winless in their last three outings which left them 14th in the table, three points clear of rock-bottom Baroka FC.
Sead Ramovic’s side came into this midweek tie winless in their last two matches, while the Maroons were seeking back-to-back victories to end off the year.
The hosts dominated possession in the first half but ultimately had nothing to show for it, with Stellies creating the more clear-cut chances.
Antonio Van Wyk had the first sniff at goal after being set up by Ashley Du Preez on 12 minutes, however, Marlon Heugh was equal to the task as he denied the midfielder from inside the box.
A well-worked move involving Sphiwe Mahlangu, Mthobisi Mngomezulu and Sihle Nduli on the right flank fashioned an opening for Ethan Brooks eight minutes later, but he was unable to find the back of the net.
Du Preez should have punished an error at the back by the Rockets on 33 minutes, but he could only blaze over on the half-volley from inside the area.
Galaxy suffered a setback two minutes before half-time when Mngomezulu was forced off through injury and had to be replaced by Augustine Kwem for only his fourth appearance of the campaign.
Ramovic brought on Mlungisi Mbunjana for Bathusi Aubaas at the start of the second half and the substitute almost made an immediate impact as he played in Marks Munyai on 53 minutes, but the defender failed to test Sage Stephens.
Nduli threatened to open the scoring on the hour mark with a stinging shot from inside the box that drew a fine save out of Stephens, while at the other end a blunder from Heugh 10 minutes later nearly let in the visitors but Msimango was on hand to snuff out the danger and spare his keeper’s blushes.
Msimango though was on the unfortunate end of the scale moments later as he diverted Judas Moseamedi’s cross into the back of his own net, and in the end it proved decisive, as Stellies walked away with all three points.
TS Galaxy (0) 0
Stellenbosch (0) 1 (Msimango OG 88′)
TS Galaxy: Heugh, Sanoka, Seedat, Msimango, Munyai, Nduli, Aubaas (Mbunjana 46′), Brooks, S. Mahlangu (Phohlongo 80′), Lekay (Mbatha 66′), Mngomezulu (Kwem 43′).
Stellenbosch FC: Stephens, Johannes (Robertson 90′), Mcaba, Van Rooyen, Letsoenyo, De Goede (Dimgba 59′), Jabaar, Kwinika, Isaacs (Moseamedi 59′), Van Wyk (Khunyedi 59′), Du Preez (Msengi 77′).