Manuel Pellegrini is fighting for his future after this remarkable surrender to gift Freddie Ljungberg his first Arsenal win.
The players, just one point off the drop zone, were booed off. Pellegrini admitted afterwards the spotlight is now on him.
“It is difficult to understand why they made those mistakes,” he said. “If you are not concentrating on defending you allow the other team to score. If you are the manager you are responsible.”
Midfielder Declan Rice added: “It is heartbreaking. We are in the rubbish at the moment. When one goes in we need to learn to keep our heads up.
“They have great players but they are all preventable goals. We need to look at ourselves. We are making the same mistakes. We are playing good football as well but making too many mistakes.
“We have to win our home games. It is horrible to hear the boos. We want to make the fans happy. But we have lost big games here. Now is the time to stay together. Games come thick and fast and we need to regroup.”
Arsenal had been staring down the barrel after Angelo Ogbonna headed West Ham in front eight minutes before the break.
But a scintillating three-goal blast from Arsenal in the second half turned the game on it’s head.
Gabriel Martinelli slotted home from close range on 60 minutes. Nicolas Pepe curled in a 66th-minute banger and Pierre-Emerick Aubameyang fired in on the turn three minutes later.
It gave Ljungberg his first win after three games in charge and Arsenal their first Premier League win since October 6.
Arsenal are now up to ninth having ended the horrendous run of form that cost Unai Emery his job.
West Ham, who ended the game in front of a half-empty London Stadium, are now winless in their last five home games.
Ahead of the victory at Stamford Bridge the club’s top brass considered replacing Pellegrini with either David Moyes or Chris Hughton, fearing a relegation fight after their huge summer investment in the squad.
The Chilean is now set to find himself back in the spotlight after his side threw away the chance of victory at the London Stadium.