The Brazilians kept their perfect record intact with a tenth consecutive victory out of ten matches this season while AmaZulu suffered a third successive loss, a first in head coach Pablo Franco Martin’s time at the club.
The visitors broke the deadlock through in-form winger Lucas Ribeiro in the 22nd minute who converted a penalty.
The 25-year-old attacker scored his seventh goal of the season as he slotted through the middle after Themba Zwane was pulled to the ground in the penalty area.
AmaZulu head coach Pablo Franco Martin raised a few eyebrows when he named 22-year-old Olwethu Mzimela in goals in place of the absent Veli Mothwa.
Just as expected the visitors monopolised possession of the ball in the opening ten minutes, reaching figures of about 80% to the 20% of AmaZulu.
Midfielder Marcelo Allende fired the first warning shot in the 11th minute following an enterprising buildup by the Sundowns.
The Chile-born man found room just inside the box after receiving a Themba Zwane pass but his attempted shot was expertly blocked off by a line of AmaZulu bodies.
Tensions build up between the two teams very quickly on and off the field with tackles flying around in the wet surface.
The benches of both teams also squared off on the touchline as Sundowns head coach Rhulani Mokwena and Martin needed restraint as they charged for each other.
The halftime break provided much-needed relief for both teams as the second stanza started more calmer and controlled.
After working their way into the game, Usuthu thought they'd found the equaliser in the 65th minute through Pule Ekstein but his close-range finish was incorrectly ruled off for offside.
In the end, Sundowns proved too strong for Usuthu and closed out the result.