Ipswich failed to reclaim second place in the Championship as Cardiff struck twice in stoppage time for a remarkable 2-1 victory.
Kieffer Moore seemed to have returned to haunt his former club 11 minutes from time and put Ipswich on the brink of collecting three precious points in the Welsh capital.
But Ryan Wintle punished slack marking in the fifth minute of stoppage time as Ipswich failed to deal with Rubin Colwill’s cross and Callum O’Dowda’s knockdown.
But that was not the end of the drama as five minutes later, and with virtually the last kick of the match, Perry Ng hooked the ball towards the far post at a chaotic corner and O’Dowda volleyed home.
The defeat leaves Ipswich a point behind Leeds, who had moved in to second spot after Friday’s win at Sheffield Wednesday and possess superior goal difference than the Tractor Boys.
Cardiff were high on confidence after three successive wins and their lively start reflected that.
David Turnbull’s rasping effort from distance was saved with some discomfort by Vaclav Hladky, and the Ipswich goalkeeper was again needed from the resulting corner to keep the Bluebirds at bay.
The ball fell to Josh Bowler at the far post and Hladaky kept out his volley with an outstretched foot.
Ng seemed certain to convert the rebound with the goal gaping, but his scuffed shot allowed Moore to clear off the line.
Karlan Grant set up Josh Wilson-Esbrand for an opening blocked by Luke Woolfenden’s intervention and Hladaky held on to Bowler’s drive at the second attempt.
Ipswich did not look like a side that had scored in 12 consecutive games, struggling to play through midfield and supply Moore with tempting crosses against his old club.
Moore had managed an early header collected with ease by Ethan Horvath – Ipswich’s solitary on-target effort in the opening period – while the towering target man flicked wide after Wes Burns had raided down the right.
Ipswich began to get a foothold in the contest as half-time approached, but Cardiff went close again as Grant wriggled free just outside the box and fired over.
There was a lengthy pause after the interval as Moore and Dimitrios Goutas clashed heads.
Moore came off worse and was only able to continue after being patched up with a couple of headbands.
Ipswich sent on Omari Hutchinson and Nathan Broadhead, fit again after a two-game injury lay-off, to find some fluency in the final quarter.
Cardiff goalkeeper Ethan Horvath had to react to bat away Hutchinson’s howitzer but he was left helpless after Harness spotted Moore.
Nat Phillips stood off Moore for the first time in the contest and the Wales striker took his opportunity, burying a left-footed shot across Horvath.
But there was a lethal sting in the tail and the late goals from Wintle and O’Dowda ensured Cardiff maintained their late bid for a play-off spot.