Usuthu needed to better Moroka Swallows’ result to at least reach the promotion play-offs, but instead lost to the Team of Choice while the Birds beat Bloemfontein Celtic 1-0.
United took the lead after just eight minutes through Deolin Mekoa, who capitalised on some woeful defending before finding the back of the net from the edge of the area.
Shuaib Walters saved at Bongi Ntuli’s feet soon after, before Sadate Ouro-Akoriko headed wide from Marc van Heerden’s freekick.
Ntuli came close again just after the break when his low shot shaved the upright, but the equaliser did eventually come on 73 minutes when Thapelo Nyongo headed home from Van Heerden’s delivery.
Ndulula should have given his side the lead with 10 minutes to go when he went through one-on-one, but his attempted chip went wide.
Walters then denied OJ Mabizela, before Kwando Mngonyama was sent off for a second yellow.
But rather than using the numerical advantage, Usuthu fell behind late on when Ntuthuko Mabasa crossed for Mohau Mokate to head home.
Maritzburg finish the season in position eight with 40 points.