United started brightly, showing determination to get a positive result by applying an aggressive press which saw them receive two early yellow cards.
However, Usuthu had the first big chances of the game with Mbanjwa's header being tipped over by goalkeeper Marcel Dandjinou before Maqokolo put his attempted finish above the bar after an excellent Ngwenya cross.
The Village Boys dominated possession but could only test Olwethu Mzimela from distance while threatening from set-pieces.
Khethukuthula Ndlovu was the first to test AmaZulu shot-stopper Mzimela in the second half, forcing a save in the 50th minute as they attempted to break the deadlock.
The home side made a triple change close to the hour mark, with substitute Wonderboy Makhubu creating a chance for Celimpilo Ngema whose shot was saved just two minutes later.
Arthur Zwane responded with three substitutions of his own and were rewarded with a penalty in the 75th minute after Tatenda Tavengwa handled the ball in the box, with Hendrick Ekstein converting from the spot.
United applied late pressure for the equalizer but saw Mzimela pull off an excellent save to tip over Lesedi Kapinga's curling effort in injury time as the KwaZulu-Natal outfit held on to advance to the quarter finals.
Siwelele FC booked their place in the Carling Knockout quarter-finals after edging Polokwane City in a penalty shoot-out following a goalless contest through 120 minutes on Saturday evening.
Golden Arrows became the first team to book their place in the Carling Knockout quarter-finals after thrashing Chippa United 4-0 at King Zwelithini Stadium on Saturday afternoon.
Mandla Ncikazi has credited Orlando Pirates for playing a significant role in his development as a coach, insisting that maintaining good relationships helped pave the way for his return to Golden Arrows.
Orlando Pirates head coach Abdeslam Ouaddou has challenged his players to believe they can end the club's 31-year wait for a second CAF Champions League title after securing their place in the group stages.
