The win, a fourth consecutive one in all competitions for Eric Tinkler’s men, was earned by a Thabiso Kutumela penalty as well as an outstanding effort in defence.
Although the home side had a fair amount of the ball possession in the first half, Maritzburg were exceptionally-well organised in their shape and system - which ensured that there was no way through.
At the same time, when the Team of Choice did spot gaps, they were quick to penetrate the City defence with some slickly-worked counter attacks.
And United were not far off from taking the lead on 19 minutes when Mxolisi Kunene whipped in a cross which Kutumela controlled neatly before turning and firing a left-footed volley inches wide.
The game remained tight as United gave as good as they got -and the match seemed to be heading to the half time break with the scores locked at 0-0.
However, after Daylon Claasen floated in cross in the first minute of added time, City defender Keanu Cupido handled the ball and a penalty was awarded.
The tension was tangible, yet Kutumela showed nerves of steel as he emphatically beat goalkeeper Peter Leeuwenburgh and slotted the ball into the bottom corner.
The Citizens stepped up their efforts to try and score after the restart, but the Maritzburg rearguard responded with some top drawer defending.
And when the defence was breached on the odd occasion, Team of Choice goalkeeper Richard Ofori showed his class, making a very good reflexive save to prevent Roland Putsche’s header going in, before making a brilliant diving save to tip Shaquille Abrahams’s thunderous strike over the crossbar.
Ofori was also exemplary in his handling of a succession of aerial balls into his box and continued to receive excellent support from his defenders as City kept on the pressure.
Maritzburg did have one or two half chances on the counter-attack, but it was mainly about working hard at the other end of the field to keep the Citizens at bay, which they did to very good effect right up until the final whistle.
"I thought in the first half our performance was exceptional," coach Eric said after the game. "This is a very difficult team to play. We absorbed a lot of pressure in the second half but we defended very well. I'm really proud of the boys."
City: Leeuwenburgh, Mkhize, Cupido, Edmilson, Mokeke, Fielies, Makola, Lakay, Mayambela, Nodada, Erasmus
Subs: Stephens, Mthembu, Putsche, Kewuti, Martin, Abrahams, Seedat
Maritzburg: Ofori, Allie, Mngonyama, Xulu, Kunene, Morgan, De Reuck, Classen, Shandu, Kutumela, Brockie
Subs: Mpandle, Moseamedi, Buchanan, Nyoni, Sangweni, Sanoka, Mekoa