TOWN’S performance coach Steve Black predicted it would take a cool head to settle this derby showdown.
But it was a firm one from Nathan Clarke which meant Town collected a sweet third successive win against their arch-rivals, and a first double over them since 1930-31.
Leeds left the centre-back unmarked as Gary Roberts swung in a 16th-minute corner, and paid the price as a powerful header beat a man on each post plus keeper Casper Ankergren.
The visitors argued that their Danish stopper had both hands on the ball when Town debutant Lukas Jutkiewicz made the challenge which led to the flag kick.
But that will cut little ice with the 16,973 Town fans in a bumper 20,928 crowd, who celebrated long and hard, both after the goal and at the final whistle.
That came after four minutes of stoppage time and following a string of top-class saves by Alex Smithies, who was once again watched by a posse of Premier League scouts, plus Glasgow Rangers manager Walter Smith.
The top teenage talent, who won his first England Under 19 cap against Spain last Tuesday, endured a nightmare full debut when Leeds beat Town 4-0 at Elland Road back in December 2007.
Town have claimed revenge for that drubbing in spades, and on Saturday, Smithies showed just how much he has matured in the intervening 14 months.
He had already denied Robert Snodgrass, Leeds’ scorer when Town won 2-1 at Elland Road in November, by the time Clarke counted.
Then, in the 23rd minute, he foiled first Andy Robinson, parrying his well-struck snap shot, then Rui Marques, saving one-handed as the Portuguese centre-back met the following corner, well delivered by Snodgrass, with a close-range header.
Leeds’ longest spell of pressure came in the second half, but again Smithies was equal to their attacks.
Robinson’s 61st-minute header was held confidently, Snodgrass’s 78th-minute shot blocked and the troublesome Robinson’s 85th-minute drive rebuffed.
Even when Smithies was beaten, by centre-back Richard Naylor’s 88th-minute header, the ball hit the keeper’s right-hand post before being hacked clear.
Leeds boss Simon Grayson argued that given the number of near misses, his side deserved at least a share of the spoils, but Town deserved reward for a performance packed with character and commitment.
They more than matched Leeds in the first half, when Everton loanee Jutkiewicz was a lively frontline force, twice bringing saves from Ankergren and having a shot blocked by Marques.
And Michael Collins, whose stoppage-time strike clinched Town’s dramatic win at Elland Road earlier in the season, came close after forcing Naylor into a mistake.
Anthony Pilkington, denied by a fine tackle from Andy Hughes as he latched onto a Roberts pass, then wasted a golden chance to put Town two up two minutes before the break when he headed over from Ainsworth’s cross.
The loss of Ainsworth to a thigh injury at half-time seemed to affect Town, who were pinned back for much of the second period without the man who had stretched Leeds in the first.
And they weren’t helped when Roberts, their fastest remaining player, was forced off in the 74th minute nursing a groin strain.
Town were robbed of two valuable outlets, but the extra workload was accepted by a solid back four who will have been delighted by this clean sheet.
As well as scoring the key goal, Clarke was dominant in his battle with Argentinian striker Luciano Becchio while Andy Butler worked hard to contain Leeds’ on-loan Bristol City forward Lee Trundle, who so often tested Town in his Swansea days.
Andy Holdsworth was cool, calm and collected throughout as he worked to limit the impact of the talented Robinson, and Robbie Williams stuck to his task against Snodgrass.
No wonder Lee Clark classed himself as a “proud manager”.
Now let’s hope Town can continue their winning ways in the less frenetic atmosphere of Crewe on Saturday.