Meanwhile, Williams was forced to make a save in the 31st minute when Gallants pressed the PSL giants, but the keeper did not get hold of the ball as it went out for a corner.
Gallants' head coach Alexandre Lafitte made what looked like a tactical change in the 35th minute when he took Doudy James, who was making his debut, out and brought on Ncube.
Tashreeq Matthews spotted Marcelo Allende in a promising spot in the 48th minute, but the Chilean hit the side net, wasting a rare chance for the Tshwane giants.
Sundowns could not break the deadlock again in the 67th minute when Iqraam Rayners was fed with a good cross by Arthur Sales, only for the Bafana forward to be denied by experienced Zimbabwean goalkeeper Washington Arubi.
The Brazilians thought they had scored the opener in the 68th minute, but Rayners' goal was ruled out for offside.
Sundowns' new signing Miguel Reisinho had a debut that he did not expect; the Portuguese international received a straight red card in the 86th minute for a dangerous challenge on Nhlapho, who was himself on a yellow card.