Teko Modise, Elias Pelembe and Hlompho Kekana made it 3-0 to Downs inside half an hour, before Mongezi got one back for the hosts.
The visitors stunned the home fans when they took an early lead trough Modise. Sundowns’ captain connected well with Pelembe’s marvellous pass and chipped the ball over Postnett Omony.
Pelembe was then on the receiving end of a brilliant through-ball from Kekana and, finding himself with acres of space, slotted home to score his first goal of the season.
Sundowns made it 3-0 in the 28th minute when Kekana unleashed a rocket of a shot from a free-kick that ripped the back of the net as Leopards conceded their 54th goal of the season.
Leopards went some way towards avoiding an embarrassment when they grabbed their opening goal 10 minutes after Sundowns had scored their third. Their captain Bobe was unnoticed at the back post and headed home Raymond Monama’s cross.
But Mushekwi compounded Leopards’ misery as he was on hand to poke home after a blunder from Omony.
Lidoda Duvha capitalised on Sundowns taking their foot off the peddle when Mabunda unleashed a shot from range that sailed into the back of the net in the 65th minute.
But Sundowns were not done scoring. Pelembe showed his skill when he dribbled past three Leopards defenders on the left side and then scored his second of the season from close range to make it 5-2.