Yet bad blood has flowed between these two adversaries for many years since Don Revie and Brian Clough ruled their respective kingdoms, with the mutual loathing even providing the basis of a fictional book entitled The Damned United, which later became a film.
An infamous punch-up at the old Baseball Ground between Francis Lee and Norman Hunter in the mid-Seventies added to the ill feeling.
It was further reinforced –not that it needed to be – by pre-match claims from Derby that an individual caught spying at a Rams training session on Thursday morning was a Leeds employee, adding a further vat of spice to the melting pot. In a dramatic development half an hour ahead of kick-off head coach Marcelo Bielsa admitted sending a member of staff and accepted all responsibility for the ‘Spygate’ offence.
It made for the most chaotic of pre-match preparations, but in comfortably the most testing week of Bielsa’s hitherto serene reign the hosts claimed what most observers will consider to be their most important victory of the season.
It was registered with a discernible swagger too in a controlled performance, which begged the question as to why the Argentine felt it necessary to send an employee to watch surreptitiously Derby train in the first place.
The final whistle was every bit as satisfying as those incredulous late events against Aston Villa and Blackburn Rovers and there was nothing remotely suspicious in the merit of this emphatic victory either with Leeds supporters heralding Bielsa in song periodically.
Almost two years to the day since a home victory saw Leeds flex their muscles in a statement of promotion intent, those in white turned on the style again to move five points clear of second-placed Norwich and seven ahead of Sheffield United in third.
It was as domineering as events in Derby exactly five months earlier, when the Whites gorged themselves in a 4-1 win, and rendered fleeting talk that a three-match losing sequence might be the precursor to another Leeds descent as wholly premature.
An agitated Frank Lampard stressed before the game that ‘Spygate’ had disrupted his side and whether that was a case of getting his excuses in first or not what was not beyond dispute was that his side could barely string a few passes together for large swathes.
After palpably struggling to cope with a furious home crowd incensed at a non-penalty award on their last trip to Yorkshire – a Boxing Day appointment at Bramall Lane – Derby again resembled rabbits in headlights on an occasion when raw, unadulterated defiance flowed from the home sections.
Equally, the intensity levels, sharpness and hunger of Leeds were a sight to behold and left the visitors gasping for air, particularly in the first half.
The tone was set in the first 45 seconds when Leeds-born Andre Wisdom bundled into the back of Ezgjan Alioski – but after pointing to the spot referee Andy Davies was alerted to an offside flag, which replays showed to be the wrong call.
It provided further controversy to an already dramatic day, but represented a mere momentary distraction to relentless Leeds, with Pablo Hernandez, a pre-match doubt, at his imperious best in the heart of operations.
His inswinging corner should have led to an opener from returning captain Liam Cooper, who scooped the ball over, but a breakthrough looked inevitable and was not too long in coming.
A corner was not cleared and Jack Clarke, in his first start at Elland Road, further endeared himself to home hearts by bamboozling Craig Bryson before firing over a sumptuous low near-post cross, which was dispatched in an instant by Kemar Roofe – for his 15th goal of the season.
A swerving drive from Adam Forshaw went close to a second before the break, with a fine saving challenge from Luke Ayling to block Mason Mount’s drive being the sole brief moment of alarm for Leeds.
Any feeling that Leeds’s lead, for all their dominance, was a narrow one, was vanquished moments into the second half at Elland Road.
The irrepressible Clarke saw his right-wing cross meekly tipped away by the unconvincing Scott Carson, with Alioski playing the ball back into the danger zone, allowing Jack Harrison to slide in from close range for his maiden goal at Elland Road.
It laid the platform for a second-half cruise on an evening when Leeds closed ranks on and off the pitch and were not to be moved.
Leeds United: Peacock-Farrell; Ayling, Jansson, Cooper; Clarke (Davis 79), Forshaw, Klich, Alioski; Harrison (Shackleton 63), Hernandez, Roofe. Unused substitutes: Huffer, Halme, Gotts, Stevens, Roberts.
Derby County: Carson; Wisdom (Nugent 45), Keogh, Tomori, Lowe; Evans (Jozefzoon 61), Bryson, Mount; Holmes, Lawrence, Marriott (Waghorn 72). Unused substitutes: Roos, Bogle, Malone, Huddlestone.
Referee: A Davies (Hampshire).