Blackwell: 'The Worst For Months'
The Whites had to win to hang onto the shirt-tails of the leading two, but this result could be looked upon as the one that ruined our automatic promotion dreams.
Leeds manager Kevin Blackwell admitted the result ... and performance ... were not good enough.
Blackwell: 'That was maybe our worst performance for two months. Collectively we were poor and we have let ourselves down. We were not creative enough or bright enough to beak them down.'
Ridsdale, blamed by Leeds fans for the club's financial problems, returned as Cardiff's executive vice-chairman and the game was less than a minute old when he was jeered.
Leeds had not managed a shot on target when Koumas delivered the killer punch. Sean Gregan fouled Koumas to the left of the D and Koumas punished him by curling the free-kick just inside Neil Sullivan's left post.
Ridsdale resisted the temptation to enjoy an extravagant celebration, remaining in his directors' box seat.
Wales international Koumas, on loan from West Brom, had scored with a spectacular shot in Cardiff's 2-1 win over Leeds in August and again the midfielder was a menace to Blackwell's side.
Leeds had little to offer and Cardiff could have taken an earlier lead when Glenn Loovens' shot bounced up off the turf and struck the bar in the 21st minute.
Cardiff goalkeeper Neil Alexander did not have a shot to save until the 34th minute when Liam Miller, on loan from Manchester United, tried his luck from 25 yards.
Leeds continued to struggle to string their passes together and left the field at half-time to jeers from their frustrated supporters.
Matthew Kilgallon almost snatched a 77th minute equaliser but Kevin Cooper made a vital clearance to help out his keeper, and Eddie Lewis headed straight at Alexander in injury-time.