Sandile Zuke got the goal for Aces.
The home side may have had nothing to play for, considering their relegation, but they played some free-flowing football and created a few decent chances in the opening 45 minutes.
Maritzburg had the first chance, however, when Byron Hendricks let fly from about 20 yards out, but his effort went wide of the target.
After that, however, Aces found their footing in the game and began to control the flow of play.
On 10 minutes a swift passing movement put Mangoba Ngwenya one-on-one with Su-Aib Walters, but he was quickly off his line and Ngwenya shot wide.
In the 21st minute Ngwenya turned provider and played Zuke through on goal.
The Aces man showed real class to chip the onrushing Walters from 12 yards out and give his side the lead.
Gert Schalkwyk came on for Musa Nyatama shortly after the goal, but the change made very little difference as United still struggled to break down the Aces defence.
But on 53 minutes Sibisi picked up the ball in the middle of the park and drove towards the goal before unleashing a well placed 20-yard shot that found the back of the net.
10 minutes later Sibisi found his brace. Felix Obada passed to him in space 12 yards out and finished clinically into the bottom right corner.
United held on to the lead and picked up a vital three points to go above Vasco da Gama and Moroka Swallows into 13th place.