Delhi took the lead in the 23rd minute through captain Kalu Uche but ATK struck back to enjoy a 3-1 advantage with goals from debutant Sibongakonke Mbatha (37th) and a brace from star striker Robbie Keane (52nd and 58th).
There was more than half an hour to be played and Delhi stunned those watching with quick goals from Uche (69th), Seityasen Singh (71st) and finally the winner from Matias Mirabaje (90+2).
The winner from Mirabaje came in the second minute of stoppage time as Delhi, who are already out of the race for the semi-finals, proved their worth.
The win means Delhi have now jumped above ATK to the eighth position with 15 points from 16 matches.
Delhi have picked up more than half of their points from the last four matches where they have remained unbeaten.
The misery for ATK and interim chief coach Ashley Westwood continues. ATK have not won a single game since the departure of Teddy Sheringham and Westwood saw his team losing five of the last six matches.
The stunning result for Delhi and the change in fortunes on Saturday overshadowed some excellent performances from ATK.
Star striker Keane scored two goals. The first was a stunning free-kick and the second an opportunistic strike after the goalkeeper had erred with his collection.
ATK's opening goal came from debutant Mbatha, who mesmerised everyone with some brilliant play on the flanks.
He was fortunate for the opening goal since it deflected of a defender and sailed into the nets but for most part of the match Sibongakonke was a treat to watch as he teamed up with Keane.
In the end, even those dazzling performances were not enough for ATK to stop their free-fall.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
