Sheffield Wednesday extended their unbeaten run in the npower Championship to four matches with a 0-0 draw at Huddersfield but were given a helping hand by referee Mick Russell in a fiercely-contested Yorkshire derby.
Wednesday, who have climbed out of the relegation zone after three straight wins over the Christmas period, should have been reduced to 10 men midway through the first half when key player Jeremy Helan was shown a second yellow card.
But Russell did not realise he had already booked the on-loan Manchester City midfielder and amid furious protestations from Huddersfield players and management, the Herefordshire official allowed Helan to play on.
Huddersfield, now without a win in nine league matches, almost snatched all three points in the final minute when substitute James Vaughan flashed a volley inches wide.
But Wednesday substitute Mamady Sidibe forced Huddersfield goalkeeper Alex Smithies into a superb save with a header moments earlier and a draw was a fair reflection of an entertaining encounter.
Huddersfield manager Simon Grayson made five changes with defenders Murray Wallace and Joel Lynch, midfielder Chris Atkinson, winger Adam Hammill and striker Simon Church all back in the side, while Wednesday recalled forward Gary Madine.
The visitors spurned a golden chance to take an early lead when Helan squeezed between two defenders into the penalty area only to see his low shot saved by the feet of Smithies.
Smithies saved again, low to his right, to parry Wednesday midfielder David Prutton's volley as the visitors, playing the more cohesive football, took the game to Grayson's side.
Referee Russell then unwittingly became centre of attention midway through the first half after booking Helan for a 26th-minute foul on Hammill.
The Hertfordshire official seemingly forgot he had already shown the Frenchman a yellow card for diving in the penalty area 17 minutes earlier, but despite animated reminders from home players and the Town bench, Russell allowed Helan to play on.
Amid chants of 'you don't know what you're doing' the referee's gaffe was also pointed out by Grayson to fourth official Duncan Street and assistant referee Wayne Grunnill, but under the laws of the game, once Russell had restarted play following the foul, he was unable to retrospectively correct his mistake.
Town carved out their only clear-cut chance of the opening half a minute before the interval.
Church's low shot following Adam Clayton's cross was brilliantly saved by Wednesday goalkeeper Chris Kirkland and the score remained goalless at half-time.
Wednesday winger Michail Antonio almost cashed in on Wallace's slip on the edge of the area a minute into the second period, but dragged his shot wide, and soon after crossed tantalisingly to the far post, inches away from the outstretched boot of Madine.
Huddersfield responded in the 59th minute, but Clayton headed tamely at Kirkland following Hammill's pinpoint cross before Grayson sent on Sean Scannell and Vaughan for Atkinson and Church respectively.
Wednesday substitute Sidibe replaced Madine in the 65th minute and Huddersfield swapped injured right-back Jack Hunt with Paul Dixon five minutes later.
Dixon was booked soon after for bringing Antonio's marauding run crashing to an end.
Sidibe lashed a 25-yard shot high and wide in the 84th minute before Sidibe's header from Rhys McCabe's corner was superbly tipped away by Smithies and Vaughan's volley shaved the post at the other end.