In a closely-contested match between two former Nedbank Cup champions (Swallows in 2009; Wits in 2010), the Clever Boys edged out the Birds thanks to a goal just past the hour mark from striker Sifiso Vilakazi.
Wits enjoyed the lion's share of possession in the first half, and looked full of running in midfield, but they were not able to create any clear scoring chances because of some solid defending by the Birds.
The visitors' only notable effort at goal came from youngster Bhongo Jayiya in the 18th minute: he got on the end of a good cross from the left flank, but mis-timed his volley and was unable to test goalkeeper Greg Etafia.
Swallows, despite seeing less of the ball, were the more dangerous team going forward. They should have been ahead as early as the eighth minute when good work from Siyabonga Nomvete set up David Mathebula with a one-on-one chance against Emille Baron, but the Wits keeper came out tops.
The Birds also had speculative efforts from 'Bhele' and Bennett Chenene in the remainder of the first half, but neither player was able to call Baron into further action, leaving the score 0-0 at the half time break.
Wits created the first proper scoring chance of the second stanza in the 58th minute, as a ball chipped over the top of the defence by Sifiso Vilakazi put his namesake Sibusiso in on goal, but Etafia moved quickly off his line to deny the young midfielder.
On 62 minutes the Clever Boys broke the deadlock. Sibusiso Vilakazi played a defence-splitting pass to put Miguel Timm up against Etafia – the Nigerian came up with another good save, but there was nothing he could do to stop Sifiso Vilakazi scoring from the rebound.
Timm should have doubled his side’s lead on 68 minutes when he was put through on goal by Lehlogonolo Maselesa, but his stabbed shot was again kept out by the excellent Etafia, the only man standing between Wits and an easy progression into the next round.
Wits were able to hold onto their lead relatively comfortably for the remainder of the match and will head into next week's Last 16 draw full of confidence that they can progress deep into the competition.