Manchester United's coach arrived late at Upton Park amid a hail of bottles from West Ham fans that recalled scenes from football's desperate days of 1970s hooliganism.
It was always going to be a highly charged farewell, after 112 years, to this football bastion of east London and the one consolation was that at least no-one was seriously injured.
This was a hugely significant fixture for the visitors too, Louis van Gaal and his players arriving with their fate in their own hands but little margin for error.
They knew victory here, amid a heady mix of nostalgia and fierce hostility, would leave them needing only to beat Bournemouth at Old Trafford on Sunday to secure Champions League football.
Instead, a 3-2 loss leaves them still needing that win against the Cherries - but now requiring that neighbours Manchester City lose at Swansea.
Has Van Gaal blown his chance of survival?
As a fleet of London taxis brought a succession of West Ham greats on to the Boleyn Ground turf for the big finish to the farewell party, several cynics suggested one cab was on order to ferry Van Gaal away from Manchester United.
It has been obvious since Christmas that there has been no great appetite inside Old Trafford to replace Van Gaal - if United were certain he was not the man for the job, former Chelsea boss Jose Mourinho could have already been occupying his office or at least officially lined up.
Even in the hours before this loss at West Ham, Van Gaal's position appeared to be gaining strength with the supposed loss of 18-year-old transfer target Renato Sanches to Bayern Munich in a £27.6m deal.
It was later suggested United had not missed out but that Van Gaal had actually vetoed the deal - and why would the club let him do that if he was not going to be in charge next season? The fact that Sanches' agent is Jorge Mendes, who would love to see his client Mourinho installed at Old Trafford, only added to the perceived political intrigue.
One way Van Gaal could have strengthened his position even further would have been a win at West Ham that would have made United firm favourites to beat City to fourth place in the Premier League, with the potential bonus of an FA Cup final victory over Crystal Palace in May.
Indeed, so buoyed was Van Gaal by the sudden upturn in his position that he was even able to point out to the media that they were finally posing tactical questions before a game rather than asking about his possible sacking.
And for four tantalising second-half minutes it all seemed on for Van Gaal. Antony Martial's brilliance had turned the game, undeservedly on its balance, in United's favour with two goals. At 2-1 up, they were 14 minutes from a win that could have offered the opportunity to put a different spin on their season.
It was not to be. Old vulnerabilities quickly returned and saw United beaten by two headed goals from Michail Antonio and Winston Reid - leaving Van Gaal back on the rack. The players dragged their manager out of a hole then threw him back in again.
The intention may still be to keep him next season but that decision would have been made a lot easier and more palatable with victory. Now it all goes on the line again on Sunday - but with Manchester City at the controls.
Who will win the battle of Manchester?
The equation is simple. Manchester United must beat Bournemouth and hope Manchester City lose at Swansea - and therein lies that sliver of hope for the 64-year-old Dutch coach.
City have been so unreliable, unpredictable and uninspired at times this season that you would not risk too much on the certainty of Manuel Pellegrini's side getting the job done.
Of course City will be favourites and only need a point - but they are not a team to be trusted, as seen in their heavy defeat at Southampton and disappointing draw at home to Arsenal in their last two Premier League games.
And after beating Liverpool 3-1 and, more impressively, thrashing West Ham 4-1 at Upton Park on Saturday, Swansea are also running into the sort of relaxed good form that makes them dangerous opponents.
Confidence has been renewed to such an extent that head coach Francesco Guidolin is expected to be confirmed on a new contract after a Swansea board meeting on Wednesday.
City can be fragile and United will hope that vulnerability haunts them one last time.
And then all it needs is for United to beat Bournemouth - but United cannot be trusted either.
Loss to Hammers symptomatic of season
Manchester United's players may have been affected by an arduous coach journey that ended in such disgraceful scenes outside Upton Park - and West Ham co-owner David Sullivan's dismissive response that the visitors should simply have arrived earlier did no credit to him or his club on this landmark night.
The kick-off was delayed by 45 minutes but there was still no excuse for a tepid Manchester United first half that lacked urgency, organisation and anything that would be reasonably expected with stakes so high.
They were lucky to only trail to Diafra Sakho's early goal, their defence going missing in its entirety shortly afterwards when Andy Carroll raced clear only to shoot straight at David de Gea.
It was as if Van Gaal had not impressed upon his players that a door to the Champions League that had looked shut for so long was suddenly ajar. Instead it looked like meaningless, end-of-season stuff.
The superb Martial offered brief hope, the normally passive Van Gaal leaping from his seat to punch the air - but the joy did not last long as the visitors' vulnerability in defence was exposed. They simply could not cope with West Ham's pressure.
For long spells this was a performance that made you question how such an ordinary side could even be in contention for a top-four place. They were that poor.
True, they missed the aerial strength of suspended Marouane Fellaini, who operated with such success to not only combat the likes of Carroll but also score when Manchester United won 2-1 at Upton Park in the FA Cup quarter-final replay.
In the final reckoning, however, this defeat was deserved after a display that produced much of the evidence that has left so many United fans questioning Van Gaal's future.
Can the FA Cup save Van Gaal?
Van Gaal will still believe his side can reach the Champions League but the odds are against them now so he may well end up looking to the FA Cup for success.
If United win he will undoubtedly paint this as progress - and he will have a point as it would be the club's first major trophy since Sir Alex Ferguson retired in 2013.
It may not be enough, however, to suggest Van Gaal is pointing United in the right direction, despite his willingness to play youth with the emergence of 18-year-old Marcus Rashford and the signing of 20-year-old Antony Martial - who increasingly looks like a bargain at £36m from Monaco.
Executive vice-chairman Ed Woodward clearly wants his man to succeed and his thoughts on the future remain a mystery but there is no doubt an FA Cup win is a much harder sell than an FA Cup win and Champions League football.