The Gold City Giants, who had signed Paballo Mngomezulu during the week and also started him, were searching for their 1st victory of their 2017/18 season.
Both teams took time to settle and most of the action took place in the middle of the park.
In the 32' Tebogo Mathopa was replaced by Dingaan Metsi as Aces looked for penetration through the Alex Uniteds tight defence.
Alex United broke the deadlock on the stroke of halftime through Andries Mosehle. 1-0 United.
At the start of the second half, Mthokozisi Yende came on Ermano Barends but it was United who stretched their lead in the 63'minute when Sam Kapu nailed a magestic volley. 2-0 United.
The diminutive striker Collen Zimba came on for Kwanele Hlatshwayo as Aces chased the game with three defenders.
Dingaan Metsi did pull one back for Aces late in the half but United held firm and recorded their 2nd win on the trot.
Aces next game will be away against Dube Continental FC at the Nike Center on 1 October.
Alex Black Aces TEAM
Rito Hlabana, Kwanele Hlatshwayo (65’ Collen Zimba), Enrico Adolph, Tsietsi Mohoa, Lloyd Dlangamandla, Suprice Hlungwane, Paballo Mngomezulu, Theo Mbiyozo, Tebogo Mathopa (32’Dingaan Metsi), O'Neil Hendricks, Ermano Barends (46’Mthokozisi Yende)
Devon Peters, Philani Khwela, Lebogang Sithole, Thomas Madimba
Friday 22 September ‘17
African All Stars 1 - 0 Dondol Stars
Saturday 23 September ‘17
JDR Stars FC 0 - 3 Maccabi FC - Balfour Park : 3pm
Valencia FC 3 - 1 Garankuwa United FC
Vaal Professionals FC 1 - 2 Baberwa FC
Alexandra Black Aces 1 - 2 Alexandra United
Leruma United FC 0 - 0 Swallows FC
Sunday 24 September ‘17
Thembisa Sport Centre vs Pretoria Callies - Makhulong Stadium : 3pm