Chiefs showed their intentions early on when Willard Katsande looked to catch Denis Onyango off guard with a shot from range, but the Ugandan was up to the task in the opening minute.
Ryan Moon capitalised on indecision from Downs to set up Dumisani Zuma, but the latter fired wide of goal after eight minutes.
Moon looked to continue his goal-scoring form with a header from a corner, but he was unable to find the net.
At this stage, Sundowns were still getting into their rhythm, but looked ominous with their high-line approach that they almost caught the hosts on a few occasions.
Bangaly Soumahoro, who put the ball in his own net the last time they visited FNB, almost did the same from Siphiwe Tshabalala’s cross-cum shot which forced Onyango to tip it onto the post after 22 minutes.
After sustaining the onslaught, Downs got into their groove and it took talisman Percy Tau to get their first shot on goal, through the head which Itumeleng Khune saved quite easily before the interval.
The chess game continued in the second half, forcing both to unleash their high-profile January acquisitions, with Jeremy Brockie entering the fray for Sibusiso Vilakazi in the 55th minute.
The Amakhosi responded with the introduction of Leonardo Castro, who faced his former employees for the first time as he replaced Moon after 63 minutes.
Brockie was unfortunate not to get on the end of Oupa Manyisa’s delivery on the 70th minute mark, which sailed across the face of goal.
Steve Komphela introduced Siphelele Ntshangase for Zuma, while Pitso Mosimane brought in Gaston Sirino for Khama Billiat 15 minutes before the end.
Amakhosi were given an early scare when Tau's shot hit the post, with the rebound effort from Brockie hitting the top of the post, as the home side had a heart-in-their-mouth moment.
In the closing stages, Katsande almost broke the deadlock from a corner, but his header bounced into the ground and over the bar.
The result leaves the Brazilians on top of the standings, while the Amakhosi join third-place Orlando Pirates on 30 points - a point behind Cape Town City.