Mamelodi Sundowns were looking to cut Kaizer Chiefs' lead at the top of the Absa Premiership log to 10 points when they welcomed Bloemfontein Celtic to Tshwane.
Celtic took an early lead in the first minute of the game, when in-form Lerato Lamola pounced onto a loose ball in the Sundowns box to net his 11th goal of the season.
The away side doubled their lead in the ninth minute through Malawian forward Frank Mhango, who dribbled past Sundowns goalkeeper Denis Onyango, before hitting the back of the net.
Sundowns were presented with an opportunity to pull one back from a free-kick in the 14th minute, but Teko Modise's effort from the set-piece was well saved by Celtic keeper Patrick Tignyemb.
Phunya Sele Sele were playing on the counter, as they absorbed pressure from the Brazilians before launching quick counter-attacks.
Things turned from bad to worse for Sundowns when shot-stopper Onyango fouled Lamola outside the his box, and the Uganda international was shown a straigh red.
Sundowns' long-range specialist Hlompho Kekana unleashed a powerful shot from 40-yards out in the 35th minute, but his attempt went just over the crossbar.
The former Celtic midfielder was again in the thick of things, combining well with his Sundowns teammate Percy Tau just outside the box, before he forced Tignyemb into a low save on the stroke of half-time.
Celtic began the second-half like a house on fire in search for a third goal, and they got it in the 49th minute when new Bafana Bafana star Thapelo Morena finished off a cross from Keagan Ritchie to make it 3-0.
On-loan Sundowns midfielder Musa Nyatama increased Celtic's lead five minutes later after receiving a pass from Mukuka Mulenga on the edge of the box, before hitting the back of the net.
Mulenga, who is also on-loan from Sundowns found Mhango who made no mistake to make it 5-0 to the vistors in the 57th minute.
From there onwards, Sundowns managed to contain their Bloemfontein opponents, but the home side looked vulnerable each time they pushed forward.
Mulenga squandered an opportunity to to make it 6-0 in the 75th minute, when effort from close range went inches wide of the target.
Both sides launched late attacks but they were unable to hit the back of the net.
The match ended 5-0 in favour of Celtic, the result that dented Sundowns' title hopes.