Glen Salmon scored for United, while Franklyn Cale and Dipsy Selolwane scored for the Urban Warriors.
Matsatsantsa created the first chance of the game in the sixth minute when skipper Ricardo Katza sent his header just wide form a free-kick.
Gavin Hunt’s side deservedly went ahead in the 14th minute when Salmon ran onto a through ball before neatly chipping the ball over the onrushing Ajax Cape Town goalkeeper Morgan Cathy.
Anthony Laffor should have extended their two minutes later when he latched onto a flick-on by Salmon to race clear of the Ajax defence, but the former Jomo Cosmos winger put his effort wide of the far post.
Nhlanhla Shabalala almost pulled the Urban Warriors level in the 23rd minute when he latched onto a corner by Cale, but the midfielder saw his low shot cleared off the line.
Laffor then hit the crossbar on the half hour mark, as Supersport continued their early dominance, but Ajax grew stronger towards the end of the half and drew level with a superb effort by Cale, whose low shot gave United keeper Andre Arendse no chance at the near post.
The score remained 1-1 at the break.
Ajax created the first chance of the second half, when Cale went on a solo run in the 70th minute, but his effort from the edge of the area, flew way over the crossbar.
George Maluleke should have handed Supersport the lead four minutes later when he found himself with just Cathey to beat, but the striker sent his effort over the crossbar from just 10 yards out.
Maluleke wasted another chance five minutes from the end when Supersport launched a quick counter, but the former Tuks striker opted to shoot at goal, which Cathey saved, when Daine Klate was in a much better position.
Cole Alexander should have scored for Ajax in the referee’s optional time when he beat the United defence before rounding Arendse, but the youngster then completely missed his kick from a yard out, with the ball rolling out behind for a goal-kick.
However, Alexander the won a penalty for the Urban Warriors in the final minute of optional time when he was brought down inside the area by Oscar Ntwagae, and Dipsy Selolwane made no mistake from the spot, to ensure that Ajax Cape Town successfully defended their Old Mutual Manguang Cup title.