What had worked so well for West Ham in their recent meetings with Arsenal conspired to fail miserably at the London Stadium.
Criticism among fans of David Moyes and his negative tactical approach have been loud and clear in recent weeks, with his side now winless in seven matches.
Here, many fans made their feelings clear as they headed for the exits at the end of the first half, with West Ham already 4-0 down and heading towards their heaviest ever home Premier League defeat.
This dismal West Ham side was unrecognisable from the one crowned Europa Conference League champions eight months ago.
The manner this defeat will only turn up the scrutiny on Moyes, and whether he is offered a new contract.
Despite having beaten Arsenal twice already this season, here his side delivered a performance he described as “weak”.
This was also West Ham’s joint-heaviest of all time, along with an 8-2 loss against Blackburn in 1963-64, and cameras panned to a glum looking David Sullivan in the directors’ box.
A promising early start included Ben Johnson impressing out of position at left wing and Mohammed Kudus seeking to run at Arsenal down the right.
But all hope soon dissipated as the afternoon unravelled at a quite ferocious rate - the hosts conceded three set-piece goals in the space of 12 minutes.
That will have been particularly sickening for Moyes, who will have watched the way centre-backs William Saliba and Gabriel helped themselves to tap-in headers. Both were left hopelessly unmarked from Declan Rice deliveries.
Alphonse Areola behind them was busy throughout and produced one or two decent stops, but it was his needless upending of Bukayo Saka in the box that handed Arsenal their second goal from the penalty spot.
Arsenal’s fifth goal was as poor as they come from a defensive perspective.
Dropping off with Saka approaching him in the box and with Emerson hopelessly out of position, Nayef Aguerd showed Saka on his left foot and he slammed home his 50th Arsenal goal.
Defensively, West Ham were horrendous, and offensively they were absent.
The final whistle was quickly drowned out by boos from those who had decided to stick it out.
