United overcome a gallant University of Pretoria 5-4 on penalties after the teams were tied 2-2 after the regulation 90 minutes in the pre-season tournament.
United fought back from a two-goal deficit to force the match to a penalty shootout.
Earlier in the day, defending Premiership champions Sundowns trounced Moroka Swallows 5-0 to secure a final berth.
In the later match, AmaTuks had their neighbours on the back foot as they went up by two goals and looked set for victory.
Defender Alan Robertson gave AmaTuks the first-half lead with 37th minute goal after a powerful run into the opposition box on the right flank.
The university club extended their lead in the 64th minute with a headed goal by midfielder Vuyisile Ntombayithethi. Just when it looked as though AmaTuks were soaring to victory, United responded with a late-match comeback.
After an extended period of pressure on the opposition, United were rewarded with a penalty.
AmaTuks captain Tebogo Monyai was adjudged by referee Daniel Bennett to have handled the ball in the penalty box, and United striker Bradley Grobler calmly converted the spot kick past goalkeeper Washington Arubi in the 72nd minute.
United, spurred on by the late breakthrough, continued to pile on the pressure on their retreating cross-town rivals.
In the 81st minute, United equalised with a headed goal from the corner-kick by defender Clayton Daniels.