Mutiny at Selhurst Park
Reds used to bellow 'attack attack attack' in the final quarter of matches but at Selhurst Park the first cries came just 20 minutes in.
"Paul Scholes he scores goals" the travelling support sang after 37.
Serenading Scholes two days after he gave Van Gaal a kicking as merciless as one of his tackles was not co-incidental.
United supporters were not merely going through the repertoire of songs reserved for former legends, they were turning against the manager who had delivered another turgid performance.
Pitiful against PSV
United's first half performance at home to PSV Eindhoven in November was actually one of the better ones this season.
Martial, Jesse Lingard and Morgan Schneiderlin wasted gilt-edged chances to put the Dutch side away as United dominated, requiring a win to seal Champions League qualification with a game to spare.
The second half, however, was one of the worst 45 minute displays ever recorded by a United side.
They did not muster a single shot on target, the team were booed off and the rot began.
A depleted United crashed out in Wolfsburg to be relegated to the Europa League weeks later and the season began to unravel.
Another January and another 1-0 home defeat to Southampton, only this time the atmosphere at the club was the most toxic since the Glazers takeover in 2005.
Boos rang in Van Gaal's ears at half-time and again at full-time, whereas the players were applauded by the Stretford End- United managed one attempt on target all game (Daley Blind forcing Fraser Forster into a catch rather than a save).
Van Gaal and his players then enjoyed two days off as rumours abounded of his sacking.
Fans had booed in previous games but against Southampton it was patently clear they held one man responsible for United's slump.
Misery in Midtjylland
Danish minnows Midtjylland had not played in two months and had won just one of their last ten games when they lined up against United in February.
What followed was Van Gaal's Olympiakos moment.
Almost every United player produced performances worthy of a minus rating to match the freezing conditions as Midtjylland became the lowest-ranked European side to beat us in the last ten years.
We managed to recover in the return leg on a night Marcus Rashford's name shot up on Google Trends, but, just like with Moyes and Olympiakos, elimination awaited in the next round.
Listless at Liverpool
Towards the end of his United tenure, the similarities between Louis van Gaal and David Moyes became so stark he presided over a pathetic March surrender to Liverpool.
Van Gaal was as fortunate as Moyes that a soulless loss to United's greatest rivals did not end in triumph for the Merseysiders.
Liverpool collapsed at Palace two years ago and did so again against Sevilla last week, providing United fans with moments of unbridled schadenfreude.
Both managers did not survive the humiliations.
This 2-0 defeat at Anfield was so startlingly listless that one United player openly questioned his team mates commitments.
He could not understand why some performed so feebly in English football's most intense match and pondered whether they even understood the history between the two clubs.
'Embarrasing' was the word used to describe the performance.
West Ham woe
Mourinho had reached a 'gentleman's agreement' to manage United after the Midtjylland farce but one thing stood in his way: a top four finish.
So lacking in quality was this season's Premier League that even Van Gaal's United were in contention to finish fourth in May.
At West Ham, we led 2-1 with 15 minutes to play but then sieved goals from two set-pieces to go down 3-2.
United's fourth placed competitors City had been wobbling for months and performed so nervously at a casual Swansea on the final day that they only managed to draw.
United won their rescheduled with Bournemouth to get level on points with City but trailed them by 16 in the goal difference column.