There were two hat-tricks on a night that is barely explainable, as both defences struggled. It is the first time there have been two hat-tricks in a PSL fixture.
Siwelele had only conceded 19 goals in 27 games prior to this one, but added seven to that total.
But Sundowns could not decisively improve their goal difference as they conceded four times.
They have played two games more than second-placed Orlando Pirates, who have a +41 goal difference. Sundowns are now on +37 and play their final match of the league campaign at TS Galaxy on Tuesday.
If Pirates win their three remaining games, they will be champions.
Early lead
Sundowns took the lead inside seven minutes as Teboho Mokoena scored his seventh goal of the season.
The ball was only cleared to the edge of the box by Siwelele and Mokoena volleyed low into the left-hand corner.
It was a superb finish that showed all of his technique and eased the pressure on Sundowns in the early part of the game.
It was a seventh goal of the campaign in 39 matches in all competitions, to go with two assists.
A quick second
Sundowns doubled that advantage on nine minutes in a ferocious start to the game as Tashreeq Matthews headed into the net.
As has been the case all season, Nuno Santos was the provider with a delicious cross from the right as Matthews ghosted in between two defenders and headed into the roof of the net.
But don’t underestimate the role of Santos, who is now up to 12 assists in the campaign to go with five goals. That is one goal contribution every two games from his 34 appearances.
Matthews scored his second with a simple finish after being set up by Leon.
The Colombian broke free on the right from Santos’ pass and squared it for Matthews to finish into an empty net at the back post.
Matthews now has nine goals and five assists in 47 games this campaign, with 12 goal contributions, including eight goals, in the Betway Premiership alone.
A third for The Brazilians
Sundowns took complete control of the contest when they added a third on 24 minutes, this time an own goal from Nyiko Mobbie.
Brayan Leon saw his shot saved by Siwelele goalkeeper Ricardo Goss, but the ball still deflected towards the goal line and was heading in.
In his attempt to clear the ball, Mobbie succeeded only in forcing the ball over his own goal line.
Siwelele among the goals
The rip-roaring contest saw Siwelele get their names on the scoresheet and make it 3-1 before the half-hour mark.
A poor attempt at a back-pass from Bafana Bafana centre-back Khulumani Ndamane was latched onto by Siphesihle Jeza, and his simple rolled pass to Ghampani Lungu provided a tap-in for the Zambian.
The same two players then combined in the second half for Siwelele’s second, with Lungu getting his second to make it 5-2.
They got a third with a little over 25 minutes to go when Relebogile Mokhuoane rifled the ball into the back of the net from the edge of the box, before Lungu completed his hat-trick from the penalty spot.
After not scoring in 23 league games, Lungu now has goals in back-to-back matches after also netting against Durban City last time out.
Leon gets a first hat-trick in South African football
Sundowns were cutting Siwelele to pieces and netted a fifth before half-time through Leon.
Santos was again involved with a lovely one-two before Kutlwano Letlhaku headed into the path of Leon to turn the ball home from close range.
Leon then added a second early in the second half when he headed in Santos’ cross, before completing his hat-trick as Marcelo Allende’s shot came back off the crossbar and he smashed the rebound into the net.
With his goals and assist, Leon is up to 16 goal contributions in 23 games since he joined the club in January, with 14 goals, nine in the league, and two assists.
It is a remarkable return and so far proves what an excellent signing he has been.