A double from Barnsley substitute Andy Gray prevented Cardiff moving into the automatic promotion places in the npower Championship as the visitors secured a 2-2 draw at Cardiff City Stadium.
A stunning Peter Whittingham strike had given the hosts a 21st-minute lead, but Gray coolly fired home just eight minutes later to level.
Dekel Keinan's first goal for Cardiff looked to have won it with eight minutes to play, but Gray's near-post header dented Cardiff's hopes of a top-two finish.
Craig Bellamy and Jay Bothroyd wasted chances after the break, with the former also furious not to be given a first-half penalty after going down under a challenge from Jason Shackell.
And Cardiff boss Dave Jones will reflect on a missed opportunity following Swansea's defeat at Derby as his side remain fourth in the table.
The game sprang to life as the visitors took the lead through Whittingham's stunning strike.
The midfielder brought down Jay Emmanuel-Thomas' high flick on the right and lashed an unstoppable left-footed volley beyond the despairing dive of Luke Steele for his sixth goal of the season.
Barnsley were level when Gray was given the time to control and slot a controlled strike into the corner beyond Stephen Bywater.
Luke Steele bravely denied Bellamy as Cardiff laid siege to the Barnsley goal, and their resistance was broken when a weighted Chris Burke cross was headed home by Keinan.
But the lead did not last long as Gray stooped to head home a Jacob Butterfield cross with two minutes to go.
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