At the beginning of a run of five home games out of six which are highly likely to decide their Championship fate, this was a desperate result and should the Millers finish the season in the relegation zone, then this day will be one that they will rue in particular.
Without taking this painful loss in isolation, Rotherham’s form at the AESSEAL New York Stadium - unlike in previous successful relegation missions - has simply not been good enough.
They may be missing supporters, but so is everyone.
The Millers have won once at home since December 12 and that is a grim statistic, even accounting for some exhilarating highs on the road.
Against a Wycombe side who had not scored in their previous five away games, Rotherham - who were unbalanced and ragged in the absence of suspended captain Richard Wood - conceded two dreadful goals in the opening 25 minutes.
The hosts switched to a back three in the second half, with Chiedozie Ogbene making his comeback from injury, but the damage had unfortunately been done, courtesy of strikes from Admiral Muskwe - who scored with less than ninety seconds on the clock - and former Barnsley defender Jason McCarthy.
Wycombe - who had propped up the table before kick-off and started the day five points behind the Millers - protected their precious gains in the second half with the intensity you would expect, while getting plenty of bodies behind the ball.
The hosts applied pressure, but lacked the wit and sophistication to break them down. The action was stop-start and scrappy and that suited those in blue perfectly as the visitors secured back-to-back wins for the first time since early December.
A professional performance was afforded gloss when more lamentable Millers defending enabled David Wheeler to slot home a late third after substitute Adebayo Akinfenwa had easily beaten Angus MacDonald in the challenge.
The smart money remains on the Chairboys going down, but they remain in the game just about and will go down fighting on this evidence.
Their second-minute opener was a gift. Joe Jacobsen’s free-kick was flicked on and Muskwe ghosted into an ocean of space before steering the ball past the exposed Viktor Johansson.
Without the presence of a three central defender and with a make-shift left-back in Ben Wiles, the hosts toiled at the back and a tough day got worse.
Muskwe and Anis Mehmeti spurned half-chances as the hosts hesitancy continued before terrific work by Uche Ikpeazu set up McCarthy, who was given far too much space before unleashing a low drive which deflected into the net to compound matters.
United, who palpably lacked width in the first half, still fashioned opportunities with Micheal Ihiekwe planting a point-blank header wide and an important touch from Jack Grimmer denying a certain goal at the back spot for Freddie Ladapo following Michael Smith’s cross-shot.
David Stockdale was kept honest to thwart Wiles and Jamie Lindsay in quick succession and also turned away a low drive from Lewis Wing, with the Millers’ number of chances at least providing them with a spot of hope in the second period.
But there was no onslaught. Wing fired just off target, while Stockdale was in the right place to prevent Angus MacDonald from reducing the arrears before salt in the wounds was applied by Wheeler as a seething Warne stood motionless in his technical area.
Rotherham United: Johansson; Harding, Ihiekwe, A McDonald, Wiles (Jozefzoon 45); Barlaser (Ogbene 45); Lindsay (Giles 76), Wing, Crooks; Smith, Ladapo (Hirst 76). Substitutes unused: Blackman, S MacDonald, Sadlier, Clarke, Olosunde.
Wycombe Wanderers: Stockdale; McCarthy, Grimmer, Knight, Jacobsen (Stewart 44); Onyedinma; Muskwe (McCleary 87), Adeniran, Thompson (Horgan 87), Mehmeti (Wheeler 45); Ikpeazu (Akinfenwa 78). Substitutes unused: Allsop, Kashket, Phillips, Samuel.
Referee: J Linington (Isle of Wight).