Manchester United defender Luke Shaw has described their latest loss as being " just not good enough."
The Red Devils suffered their 13th defeat of the season, as West Ham ran out 2-0 winners at the London Stadium.
Man United have now gone four games without a goal for the first time since 1992 with another dire display.
Shaw said: "It's just not good enough really, we have to win games and that's it.
"We keep losing games, losing points and we're making it very hard for ourselves – especially that second half, it's not good enough.
"In the first half, we controlled the game, I think we had chances again. If we score the first goal, maybe the result is different, but we don't, so we suffered in that second half and, again, it's not good enough."
Second-half goals from Jarrod Bowen and Mohammed Kudus lifted West Ham up to sixth in the Premier League, while United slid down to eighth.
Hammers boss David Moyes came in for criticism for making six changes in their 5-1 Carabao Cup defeat at Liverpool in midweek.
But the Scot stood by that decision as he looked back on a largely successful 2023, including West Ham's memorable Europa Conference League win last season.
"Our record here at home is as good as most," he said. "Of course we can think of clubs who will do better, but for us we've had a brilliant year.
"The players we've had, whether they've gone or whether it's new ones we've brought in, we've had a fantastic year, with a trophy in the middle of it.
"It looks like if you don't quite give everyone what they want then you get criticism for it, but I don't think we could have won on Saturday if we had played all the players in midweek."