- Joachim Andersen (25')
Having tasted defeat in their previous home league match, against Brighton, the below-par hosts again found themselves behind in the 25th minute as Anderson arrowed into the top corner.
With plenty of time to find a leveller on home turf, clear-cut chances remained few and far between in the Manchester rain, with Palace goalkeeper Sam Johnstone enjoying a quiet afternoon.
Mason Mount missed United's clearest opening in the second half, with Palace seeing out a victory that moved the visitors up to ninth in the standings, one place above the 20-time top-flight champions.
With nine points and a -4 goal difference, this is Manchester United's worst-ever start to a Premier League season after seven games. The last time they suffered a worse start to a top-flight campaign was in 1989-90.
United lost convincingly to Brighton two weeks ago to bring an end to their 31-game unbeaten run at Old Trafford in all competitions.
Erik ten Hag's team had not lost consecutive home games since losing to Liverpool and Manchester City in October and November 2021 prior to Palace's visit, and the signs were good early on in the Manchester rain.
Big money close-season signing Rasmus Hojlund went close to an early opener as he lofted the ball over Johnstone only to see his effort cleared off the line.
However, Anderson's bolt out of the blue, an arrowing strike into the top corner after being left all alone from a free kick, gave home supporters a sinking feeling once more.
The hosts struggled to create further openings of note in the first period, but came out for the second half with added impetus, with Johnstone immediately forced into two fine saves.
After Mount's chance came and went, other than a few goalmouth scrambles as things got desperate, Palace remained largely untroubled, with boos ringing around Old Trafford at the final whistle.
- Chris Kavanagh
|Brighton & Hove Albion||15||7||4||4||+5||25|
|West Ham United||14||6||3||5||0||21|