Chippa rang the changes after losing their last two matches to Highlands Park and Orlando Pirates in the league and Telkom Knockout respectively.
As the only unbeaten side thus far, Downs set their tone earlier on, running at pace whilst pressing the hosts high from the offset.
Chippa though nearly caught them off guard after Ruzaigh Gamildien got behind the defence to get a snap shot that flashed across the face of goal in a lively opening to the game.
Sundowns carved out the defence easily with Lebogan Maboe and Andile Jali teeing up Gaston Sirino but Daniel Akpeyi rushed off his line to clear the danger.
The Uruguayan did made amends soon when he blasted home from inside the box after getting a pass from Maboe.
Sundowns ran the show completely and whenever on the ball, looked like scoring especially when on the attack.
Bafana Bafana international Jali hit the woodwork just before the half and hour mark from the far post off a cross by Maboe.
The Chilli Boys asked a few questions as the half dawned but Downs defence kept a good high-defensive line to went into the break in front.
Both sides returned in unchanged for the second half, with Chippa having their work cut out for them to stage a come back.
In a slight spell of dominance from Chippa, the Tshwane outfit kept their cool and restricted them to limited openings.
On the half and hour mark, there was changes off the bench from either side. Tercious Malepe came on for Chippa and Jose Ali Meza for the visitors.
With a quarter remaining, a glancing header from Mark Mayambela almost caught Denis Onyango off guard with the ball sailing narrowly wide of target.
From close range, Andile Mbenyane failed to nab the equaliser after being perfectly set-up by Lerato Manzini.
Sundowns wind down the clock in the final stages, keeping the visitors in check to grab their third win, their first since September 19 against Golden Arrows.