They may have been in the old Third Division but that mattered little as a record crowd of 49,309 flocked to Hillsborough for an 11am kick-off.
It was the first league meeting of the clubs since 1971 and it was United who went into the match as favourites, Harry Haslam’s side well placed for promotion while the Owls were six points adrift with two wins in seven games.
However, the first half hour produced little to separate the teams before the hosts threatened a breakthrough when Blades defender Tony Kenworthy was forced to make a goal-line clearance from Andy McCulloch’s glancing header.
It was a sign that the balance was about to tilt.
Ian Mellor was inches wide with a diving header before he unleashed a 25-yard drive which had goalkeeper Derek Richardson, in only his second game for the Blades, clawing vainly in the air as the ball flew into the back of the net. The Owls a goal to the good with five minutes before the break.
United hit back at once and should have been level before half-time only for Bob Bolder to push Jeff Bourne’s rising shot against the bar with John MacPhail slamming the rebound against the stranded goalkeeper’s body.
Wednesday rode a little luck but they looked to make it count, Mellor and Jeff King both hitting the woodwork before United lost their captain Mick Speight 12 minutes into the second half with injured ribs.
It then went from bad to worse for United who conceded two goals in two minutes as the Owls effectively claimed victory.
Kenworthy had been United’s best player but his slip allowed McCulloch to break away midway through the half and his cross allowed Terry Curran to fling himself at the ball and guide a diving header into the net.
Two minutes later Brian Hornsby fed Curran, the winger sprinting from halfway up the right wing before passing to King who smashed the ball past the keeper from 15 yards.
It was more than an uphill struggle for United for whom Alex Sabella had had minimal impact that day, the Argentinian being firmly and physically dealt with by the Wednesday defence.
There was a little tetchiness from a shocked Blades side, John Matthews and MacPhail both going into the book.
Wednesday’s victory was complete in the 87th minute when Mark Smith steered the ball home from the penalty spot after Richardson had hauled down Curran.
The match has gone down in Sheffield folklore, Wednesday gloriously revelling in the Boxing Day Massacre ever since.
The result also changed the course of the season for both teams: Jack Charlton’s Wednesday kick-starting a run which saw them earn promotion to the Second Division while United were kicked right out of their stride and finishing in mid-table.
Curran became a figure United fans loved to hate before he joined the Blades later in his career. He said: “It’s tremendous to win 4-0 in front of nearly 50,000 spectators.
“It was a good match and a great day for the city. I just feel a little bit disappointed for United.”
Charlton felt “the scoreline flattered us a little but we got stuck into the job well and when we got the chances we put them away.”
United boss Haslam said afterwards: “Losing Mick Speight to injury was a bad blow to us but the real reason we lost was sheer lack of discipline at the back.”