For the most part, the first half failed to spark to life with chances on goal few and far between, while in the second period, the hosts came out firing and scored through Emiliano Tade and Bonginkosi Ntuli.
The Cape side enjoyed some good early possession yet it was AmaZulu who had the first clear opening of the night when Ntuli’s 23rd-minute effort following a deflected Tade shot beat City keeper Sage Stephens, only for Keanu Cupido to clear off the line.
The visiting side’s only real attempt on goal in the opening stanza came four minutes later when Thabo Nodada’s low shot from 25-yards out was saved by Siyabonga Mbatha.
The KZN club started the second half with purpose and had chances as Ntuli’s shot went straight at Stephens before Tade’s well-struck effort was blocked by Kwanda Mngonyama.
The pressure paid dividends for Usuthu in the 62nd minute when Thembela Sikhakhane burst down the right before pulling the ball back for Tade, who controlled the ball before passing it into the corner of the net from 10-yards out.
It got even better for the lively home fans three minutes later when Ntuli squeezed in a shot from a tight angle past Stephens after some sloppy defending all round by the Cape Town side.
The Citizens briefly hinted at a fight-back, but it never materialised as AmaZulu played out the final 20 minutes without much threat to their goal as they advanced through to the quarter-finals at the expense of the 2018 MTN8 champions.