The Cape side had the better of the opening 45 minutes, but the Team of Choice came storming back in the second half, only for the equaliser to elude them.
After two missed chances by Citizens striker Siphelele Mthembu and one by Roland Putsche, the visiting side took the lead in the 44th minute after Keanu Cupido nodded in a header following the hosts' failure to clear a corner.
It was a different game after the restart as United came out firing and substitute Mohau Mokate was not far off levelling the game in the 46th minute when he flashed a header just wide.
Maritzburg attacker Deolin Mekoa then sent a drive wide on 53 minutes as United upped the ante further, the match becoming increasingly physical and competitive.
The KZN capital city club had their best chance of the game came 13 minutes from time when Tholang Masagela did well to fashion space for a shot just inside the City box, but Dutch keeper Peter Leeuwenburgh made a brilliant save to keep out the effort heading for the bottom corner.
United, who handed a debut to Justice Figuaredo, kept fighting right till the end. But some determined defending from the Cape Town team saw the hosts' chances limited as they failed to force the match to extra time.
The Team of Choice now turn their attention to Friday's mouth-watering Absa Premiership showdown against Kaizer Chiefs at the Harry Gwala Stadium.
Maritzburg United: Ofori, Sanoka, Xulu, Shandu, Thlone, De Reuck, Ndlovu, Buchanan, Mekoa, Makgalwa, Kunene.
Subs: Mpandle, Mokate, Matima, Farmer, Atouba, Masegela, Figareido.
Cape Town City : Leeuwenburgh, Mkhize , Fielies, Cupido, Kouassi, Nodada, Putsche, Patosi, Norodien, Ralani, Mthembu.
Subs: Stephens, Kewuti, Martin, Matsi, Links, Nana, Rusike.
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