It was a tight affair as both teams toiled hard all game long.
In the opening exchanges Siphelele Magubane fashioned a dipping drive from a free-kick which was saved by Platinum Stars goalkeeper Mbongeni Mzimela.
Golden Arrows repeatedly looked threatening on the counter attack - in the 21st minute a quick attack saw Mahachi tee up Lerato Lamola at the far post whose shot was well saved by Mzimela.
The first half panned out with neither team being able take charge of the game.
The second half began with a double sub from Arrows as Musa Bilankulu replaced Thabo Molefe and Nduzuzo Sibiya came on for Wayde Jooste.
In the 52nd minute Enocent Mkhabela had an opportunity to open the scoring as he headed towards goal but his effort was thwarted by Nkosingiphile Gumede.
Dikwena were the brightest off the blocks in the second half but the deadlock was proving tought to break.
Fifteen minutes from time Thabang Sesinyi's powerful strike came close to being the opener only for Gumede to excellently parry the ball over.
However, Arrows were awarded a penalty in stoppage time as Knox Mutizwa was fouled by Ryan de Jongh. Mahachi stepped up to convert the resulting penalty to hand Arrows all three points.