The Brazilians created most of the chances throughout the match but Daniel Akpeyi was in good form in the Chippa goal, notably keeping out two shots from Tebogo Langerman in the first half.
Langerman suffered an ankle injury later in the game and had to be replaced by Mzikayise Mashaba, while Pitso Mosimane brought on Khama Billiat at the start of the second half for Cuthbert Malajila, who also appeared to be injured.
Roger Sikhakhane made a double substitution for the second 45 minutes, bringing on Lerato Chabangu and Rhulani Manzini to inject some more creativity and pace to take the game to Sundowns.
But Keagan Dolly gave Sundowns the lead in the 60th minute with a sumptuous half-volley from the edge of the area following Themba Zwane's right-wing cross and a knock-down from Bongani Zungu.
Then Hlompho Kekana made sure of the result with a deflected goal four minutes from time. Khama Billiat laid off a neat backheel on the edge of the area and Kekana's shot was wickedly deflected off Kuduku Maleasenya and past a helpless Akpeyi.