As early as the third minute, the National First Division side took the match to the hosts when Mxolisi Mayongo saw his attempted header from a good position flash wide.
However, the Brazilians bounced back three minutes later when Dolly failed to pounce on a rebound in the box, with his shot going over goalkeeper Thuto Xaba’s posts.
Just after 10 minutes of action, Khama Billiat tried a long-range shot but the Zimbabwean’s effort was also off target, failing to trouble United’s keeper.
Despite enjoying much ball possession, Pitso Mosimane’s men couldn’t create clear-cut chances until the 24th minute when Zwane combined with Dolly, who shared the ball with Billiat. In the end, Billiat laid the ball off to the unmarked Dolly, who finished with ease in the penalty area to hand the Tshwane side a deserved lead.
Towards the half-hour mark, Billiat continued tormenting United’s left back Zolani Nkombelo and upon reaching the box he picked out Tebogo Langerman, who missed the target.
Sundowns continued to pile pressure on their visitors and Billiat broke free close to the d-line, however, his well taken curler went high over Xaba’s far corner.
In the 34th minute, Nkombelo tried to beat goalkeeper Kennedy Mweene from long range but the Zambian was alert and collected easily.
It was 1-0 at halftime for the Absa Premiership log leaders, and the hosts continued where they left off when a cross down the right from Zwane found Langerman, who wasted a golden opportunity as he ballooned his shot over.
In the 58th minute, Dolly missed their best chance in the second half when he received a great ball from Malajila, but the South African under-23 star rushed his shot and missed the target.
Sundowns made it 2-0 and Zwane was influential once again when he dispossessed United and beat a defender before setting up Malajila for the second goal – the Zimbabwean finished easily in the 68th minute from close range.
United improved towards the last 10 minutes when Inky Masuku’s free header hit the woodwork and went off for a goal kick.
However, a well-worked move by the visitors allowed them to grab a goal when Mnguni scored from a rebound in the box, beating Mweene.
The NFD side thought they had equalised with 12 minutes to go but the referee ruled their effort offside.
As the visitors were still celebrating and protesting, Sundowns attacked and Zwane made it three in the 79th minute when he finished a sweet pass from Billiat after turning defence into a counter attack.
In the end, Sundowns held on to their lead and they booked their ticket in the quarterfinals, increasing their chances of defending their trophy.