Fans of West Ham stormed out of the stadium after Chelsea Oproer in the London Stadium.
The hammers opened the score in the sixth minute, but that was the last thing that the faithfulness of the house had to cheer.
Chelsea lasted only nine minutes to the level, via Joao Pedro, and it was a way in which traffic was from that moment, although West Ham had a goal for offside after a VAR control.
Pedro Neto then scored to lead visitors before goals from Enzo Fernandez and Moises Caicedo the hammers sank.
The Fernandez strike led some fans to go to the hall ten minutes before the half-time whistle, with the fourth goal that caused a massive exodus.
Proponents began to leave the stadium in their throws before the hour.
That meant that they were lucky not to see Trevoh Chalobah in a fifth for the visitors.
West Ham opened their prem campaign last week with a 3-0 defeat in Sunderland.
They have now admitted eight goals – their highest number in the first two games of a season.
And to make things worse for Graham Potter it came across the club that fired him in April 2023.
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There were empty seats in the London Stadium by the time the last whistle blew.
The match ended in a thunderous 5-1 victory for the blues.