The visitors were already facing a 4-0 deficit 31 minutes after kick-off at Selhurst Park thanks to Michael Olise’s headed opener and an audacious overhead Eberechi Eze effort as well as the first of two for Jean-Philippe Mateta and an Emerson own goal.

Antonio clawed one back before the break and Moyes’s men could take no credit for their second, a late own goal credited to Dean Henderson, who turned in Tyrick Mitchell’s backpass one minute from the final whistle.

Moyes, who shot back tersely when asked about his job security, was far more forthcoming when it came to his scathing assessment of the Irons’ performance, saying: “The first half was as bad as I’ve seen us play. We’ve had three or four of these incidents.

“I don’t think the team in the three years I have been here have gone to the depths, in three or four games this year. The first half was unacceptable. We mainly were defending, the way we started the game, we’re not connected in the way we’ve played.

“You can’t play this level of football in the Premier League. We didn’t compete. It was hard to actually explain it.

“I’m so disappointed for the supporters who came here today and in truth I’m embarrassed to sit here and actually be speaking on behalf of the team and the way they performed today but I’m the manager.

“I’ve got to say I’ve not had many teams who have played like that in my whole career.”

Moyes refused to blame tired legs from last week's 1-1 UEFA Europa League quarter-final second leg draw with Bayer Leverkusen as an “excuse”, although when pressed for a “reason”, he conceded the tight turnaround probably did not help.

While he was adamant defeat at Palace would have “nothing do do with” how he would approach potential contract negotiations, when asked if his side’s performance could take the choice of a continued tenure out of his hands, simply replied: “If it is then it is” then later refused to take further questions on the subject.

The Hammers’ chances of returning to Europe next season look improbable as a result of the loss at Selhurst Park, although Moyes said his side will keep fighting until its fate is sealed.

He said: “We might still have a chance. Because we lost a couple of games doesn’t mean we don’t still have a chance. We still do have a chance. We’ll keep going, keep trying to do it.

“We’re just off the back of three years in Europe and it now sounds as though you’re talking about West Ham as a regular European team which is a big compliment, thank you very much.”

Palace sealed back-to-back wins for the first time this season after a 1-0 triumph at Liverpool. It was a third win for boss Oliver Glasner since he replaced Roy Hodgson in February.

Glasner pointed to the easing of the injury crisis that has plagued Palace all season as a key factor in its improvement, with victory over West Ham still a rare chance to witness what the Eagles are capable of when the influential Eze and Olise are both healthy.

He added: “That’s our first back-to-back win and this is our challenge: to keep this motivation high, to keep the way we want to play in offence and defence.

“Because you always have to be concentrated, stay in your position, move the ball quick so that they don’t get the ball and this always starts in your mind if you are focused and concentrated.”