The result equalled the biggest margin of defeat in the history of Sundowns football, but the real blow came with the dropped points in their slim title challenge.
Sundowns remain on 47 points, 13 behind the table-topping Kaizer Chiefs with five games left for the Brazilians. The huge margin means Chiefs need only three points from their four games remaining this season to secure top-honours.
For Celtic, the massive result moves them to 37 points as they strengthen their fifth spot on the log.
Earlier, the Sundowns defence gave the ball away carelessly within the first minute, and Celtic midfielder Musa Nyatama burst through into the area on the left hand side and his cross was parried away by keeper Dennis Onyango. Lerato Lamola was on hand to snap up the rebound and deposited the ball into the back of the net for a 1-0 lead.
Celtic had their second with just nine minutes gone. The Sundowns defence were caught napping again as the perfect pass from Keagan Buchanan drew out the keeper, but Gabadinho Mhango got the first touch away from Nyango before turning and lofting the ball into an open net for a 2-0 lead for the visitors.
Teko Modise attempted to pull a goal back in the 14th minute. His free kick drew the attention of Celtic keeper Patrick Tignyemb who made the save.
To compound the woes of Sundowns, Onyango was forced to come out of the box when Lamola broke away from the home defence and the keeper, as the last man, took out the player. The referee had no choice but to give Onyango a red card to reduce the hosts to 10 men in just the 24th minute.
With a man down, Sundowns had to resort to speculative efforts. One such occasion was in the 39th minute when Hlompho Kekana reeled off a shot from way out, and his well struck attempt was only inches over the target.
Celtic started the second period the same as the first, and had their third goal of the evening in the 49th minute. Keegan Ritchie made a fine run down the left, and he produced a stunning pass to Thapelo Morena who was unmarked in the right hand side of the area and made no mistake to make it 3-0 to Celtic.
Five minutes later, it was 4-0 to Celtic as the defending champions league aspirations were left in tatters. The pass came in from Mukuka Mulenga for Musa Nyatama who produced a good strike from the edge of the area to find the left hand side of goal.
In the 57th minute, the massacre was complete as Celtic smashed in their fifth. The cross came in, and with three Sundowns defenders simply watching, Mhango picked his spot as headed the ball in for a 5-0 scoreline.
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