Masandawana began the match brightly with Thapelo Morena lifting his second minute chance over the bar before Ronwen Williams reacted quickly to block a low shot five minutes later.
Former Arrows star Siyanda Ndlovu opened the scoring in the 14th minute after he squeezed home his first goal for his new club from a tight angle following a low driven cross from Tashreeq Matthews.
Matthews continued threatening the Abafana Bes'thende goal, forcing a save from Thakasani Mbanjwa at the half hour mark before Ayabulela Maxwele almost equalized against the run of play, forcing Williams to parry away for a corner just before half-time.
Colombian striker Brayan Leon had the first big opportunity of the second half for Downs in the 50th minute but could only direct his shot straight at the goalkeeper shortly before a triple substitution by Miguel Cardoso.
However, Arrows forward Sede Junior Dion equalized for the home side in the 76th minute following a lapse of concentration in the Sundowns defence to net his third goal in three matches against the Tshwane giants this season.
Both teams struggled to find a winner in the final moments of the match before Bafana Bafana talisman Teboho Mokoena produced a long range 88th-minute winner to steal the three points in Umlazi D-Section, Durban.
The result sees Arrows move to eighth position on the league table while Ka Bo Yellow remains second to Orlando Pirates due to an inferior goal difference.