Supporters bussed in under police escort, a tense, fractious game played in something approaching a state of war and horses drafted on to the pitch at the final whistle to keep the peace. The 991 Leeds fans who braved the New Den may have been reminded of football's dark past, but they will be much more concerned with the present, which threatens to be even worse.
On the pitch, Neil Harris's clinical finish was enough to earn Millwall first blood on the road to Wembley and leave Leeds's dreams of taking their first step to rebirth hanging by a thread. Off it, the Metropolitan Police earned a far more emphatic victory.
There was spite in the stands but no blood on the streets, the easy prediction of doom-mongers when football's two great pariahs found themselves paired in a sudden-death tie. Casper Ankergren, the Leeds goalkeeper, will leave Bermondsey with unhappy memories of a confrontation with a fist-shaking yob after Harris's strike, but otherwise the police, 400 strong, kept a clean sheet.
Their afternoon was hardly made more comfortable by the enmity which the teams clearly share from their previous encounters since Leeds's descent. Jermaine Beckford's every touch was jeered, Jason Price limped off after barely quarter of an hour after one heavy tackle too many. Robert Snodgrass and David Martin butted heads, the otherwise subdued Fabian Delph was cautioned for a wild swipe at Graham Alexander.
Amid the snarling aggression, the din of the Millwall roar and a litany of fouls, there was little time for anything resembling football. Grace was sacrificed for tenacity, silk for steel. Until Harris struck, tackles, not shots, earned the most rapturous applause.
Leeds shaded the opening hour, Luciano Becchio going close either side of half-time and almost setting Beckford free with an ingenious back-heel. In this atmosphere, though, Millwall were always likely to stir themselves.
Harris — 'maybe it was written he would score,' suggested Kenny Jackett – had already seen Sam Sodje produce one stunning diving header to deny Gary Alexander and drawn a fingertip save from Ankergren when he calmly collected Alexander's cross after Richard Naylor's slip and slotted past the Dane.
It was enough. Leeds, the wind out of their sails and their appetite for the fight diminished, ground to a halt. Grayson was not too disheartened, praising his defence's resilience, no doubt glad to have escaped the inferno with his side 'still in the tie.'
Both he and Jackett know this was but a preliminary skirmish. The showpiece battle comes on Thursday.