United crashed to a 3-1 defeat at Stamford Bridge after a Samuel Etoo hat-trick saw them off in Jose Mourinho's 100th Premier League victory.
Below are five things learned from United's deflating result:
Was Moyes right to drop Kagawa and Fletcher?
After United's excellent result against Swansea last week it was some surprise to see both Darren Fletcher and Shinji Kagawa dropped from the starting line-up. With both players on the bench and having impressed against the Welsh outfit, Moyes went for the defensive Jones who struggled to do his job in the team. Likewise, Ashley Young failed to have an influence on the game after coming in for Kagawa, and it was surprising that the Japanese star didn't make the pitch at all.
This is the kind of match where United would always miss Rooney and Van Persie
With Adnan Januzaj busy in the first half and United very much in the game, both Rooney and Van Persie were big misses for a side struggling to create and get on the end of chances. Any team is likely to miss such a frontline, and once one or both return, United will be a much better outfit. Their absence was particularly felt in such a high profile fixture.
Is it a good thing or a bad thing that Januzaj is consistently United's best player?
On one hand, it's great that United have a truly promising young player that is clearly likely to turn into one of the league's best. On the other, where are all the other players that should be stepping up and helping him out? Where is Michael Carrick orchestrating play from the middle of the park? Where is Antonio Valencia and his penetrating runs and crosses? If you sprinkle the players missing from the first team back in the side, perhaps there is a greater chance for United to seize control of matches, but of course, there is still much room for improvement in central midfield in particular.
Vidic and Rafael's challenges showed United were out of ideas
Though Nemanja Vidic's challenge was a debatable red, Rafael's almost certainly should have been, and both challenges reeked of desperate disappointment and cluelessness. United had struggled to get back into the game until Hernandez scored, and then struggled to make much further impact on the game, and David Moyes now has to deal with his captain being suspended for three crucial games - the one idea the Scot wouldn't have wanted to entertain.
United shouldn't get too carried away with this defeat but…
This match wasn't all doom and gloom though. United were arguably the better team in the first half, and were very unlucky to come in at the break 2-0 down. Losing to Chelsea away is hardly comparable to some of their home defeats this season, but the fact they do keep losing games despite spells of good play, to teams throughout the league, is a cause for concern. Losing the match itself, to a deflected shot and some poor defensive lapses isn't the end of the world, but that they already have 7 losses, 2 more than the whole of last season, hints at real problems in the team's mentality.
image: © joncandy