The 10-men AmaZulu with the late goal salvaged a point against the old foe in the KZN derby.
Mondli Cele fired the hosts to a lead in the 37th-minute that looked set to steer United to victory after Bornwell Mwape was red-carded in the 72nd minute.
The visitors created the first chance of the night when Goodman Dlamini’s
long throw into the box was not dealt with by the home defence, allowing
Ndululu to strike wide of target.
At the other end, United captain Ashley Hartog should have done better than plant his eight-yard header from a Thokozani Sekotlong cross over the bar.
Moments later Cele saw his shot fly across the face of goal from a rebound, after a wayward effort by team-mate Khumbulani Banda.
With the stronger pressure being applied by the home side they were duly
rewarded with the opener seven minutes from the break when Terrance Mandaza slipped a pass to his left, where Cele squeezed the ball past goalkeeper Siyabonga Mngoma.
AmaZulu introduced Ayanda Dlamini after the break and the striker was
immediately put into some space in the box, but failed to punish the opposition.
Dlamini made another run but chose the wrong option again, when he tried to shift the ball onto his favoured right foot rather than shoot with his left.
Mwape then received a straight red-card for a flagrant tackle on Hartog that left referee Victor Hlungwani with little choice.
Mohammed Awal was penalised for a pull on Ndulula in the box after some persistent pressure from the opposition.
Banda, Ntuthuko Mabaso and Sekotlong had wonderful chances to win the game late on, but each of them were thwarted by some excellent saves by Mngoma.
Hartog was nearly a hero but his header struck the bar at the death as AmaZulu survived.
The Team of Choice remained fifth in the Premiership, while Usuthu remained bottom of the table.