David Moyes says Dominic Calvert-Lewin's match-winning goal was a "terrible" one to concede by West Ham United on Sunday.
Everton secured a vital win over the Hammers when Calvert-Lewin latched onto Ben Godfrey's through ball and then fired past Lukasz Fabianski in the 24th minute at the London Stadium.
The Blues came close to adding a second late on in the second-half, when substitute Josh King headed against the post, yet much of the game after Calvert-Lewin's goal was dominated by Everton's defensive work.
West Ham finished with 69% of possession but failed to muster a shot on target with Vladimir Coufal's effort, which struck the inside of the post, the closest they came to equalising.
Moyes said his side did not deserve to lose the game and did not hold back in his analysis of the game-changing goal.
"I was pleased with our play, our play is improving. I have been trying to work on it and get better. We showed that for long periods of the game but we didn't have the difference upfront.
"We gave them a terrible goal. Nearly all game there were very few chances."
Moyes added: "It was terrible defensively, from my point of view. Too easy to score against.
"We've done well [this season] but when really competing you have got to be right on it, all of the time, but we just switched off for a second."
