Teboho Mokoena (6') opened the scoring for the Betway Premiership title-chasers before a quick-fire Tashreeq Matthews (8') goal and Nyiko Mobbie own-goal (24').
Gamphani Lungu (29') pulled a goal back for Siwelele but Matthews (36') and Brayan Leon (41') heaped more misery on Lehlohonolo Seema's side before Lungu (49') pulled another goal back after the break.
The action continued to flow from end to end and Gape Moralo out the ball in his own net to further extend Sundowns' lead.
Leon (58') then got his second of the night, as Relebogile Mokhuoane (64') found the target at the other end. Lungu completed his hat-trick in the 80th minute.
Speaking after the game, Cardoso said he was delighted to have been so lethal in attack but questioned their defending.
"I think we scored another goal that was quite fair and not offside, so when you risk so much and put so much energy, there will be moments where you master your defence or you cannot do it," Cardoso told SuperSport.
"I understood the energy of the boys inside the pitch was to score and score, but really to achieve a result in a match like this, that could give us seven, eight, nine goals, you cannot suffer four," he said.
"Otherwise in the end it's the same as winning three or four-nil — our defence could not really cope with the capacity the attack showed. We also had less numbers in balancing the team of course."
Cardoso added: "Important win and three points, three points away from finishing the league, with one match. Let's win the match and see what comes from there."
Sundowns play their last league game of the season away to TS Galaxy at Mbombela Stadium on Tuesday 12, May.
They then face AS FAR in the CAF Champions League final over two legs, on Friday, 15 May and Sunday 24 May.