City opened the scoring in the 15th minute through Rendani Ndou in Atteridgeville. However, Nkhatha responded with a brace before Brockie and Dove Wome added goals after the break at Lucas Moripe Stadium.
Polokwane drew first blood when the excellent Jabu Maluleke set up Ndou, who fired an unstoppable long-range, left-footed shot into the corner to put the visitors in front.
The equaliser arrived in the 25th minute, with Nkhatha capitalising on a poor goal kick from Modiri Marumo that was mis-controlled by Jabulani Nene. The striker’s snap shot was not especially well struck, but still somehow beat the City goalkeeper.
In the 28th minute Nkhatha provided an excellent finish with a diving header, glancing home David Mathebula’s right-wing cross via the inside of the far post to make it 2-1 to SuperSport.
SuperSport made two changes at the start of the second half, with Wome replacing Nkhatha due to injury, while Michael Morton was brought on in place of Morne Nel to bring some steel to the hosts’ engine room.
Wome created United’s third goal in the 51st minute, crossing with the outside of his right foot from the left flank to set up Brockie, who did just enough to beat Marumo and rack up his third goal in as many games for Matsatsantsa.
Wome then went from provider to scorer in the 66th minute when he sprung Polokwane’s offside trap, raced through on goal and fired a missile past Marumo to make it 4-1.
Both teams created numerous chances to add to the score line in the final quarter of the match.
The last-16 draw will take place in Johannesburg on Thursday.
The following teams are also in the next round: holders Orlando Pirates, Kaizer Chiefs, Mamelodi Sundowns, Bloemfontein Celtic, Ajax Cape Town, Platinum Stars, Bidvest Wits, Mpumalanga Black Aces, University of Pretoria, Black Leopards, Jomo Cosmos, Golden Arrows, Maluti FET College, Vasco da Gama and Natal United.