Midfield strength
If the departure of Nemanja Matic this summer is supposed to signal a changing of the guard to Scott McTominay, then this match was proof that is not an option for Manchester United.
Matic had a steady game in United's midfield, but McTominay was outthought and outbattled in the centre of the pitch, while his distribution was woeful.
There were times in the game when United's midfield was missing in action. Bruno Fernandes is always going to have moments where he turns into a positional maverick, but N'Golo Kante and Jorginho were given the freedom of the pitch far too often.
READ MORE: United player ratings vs Chelsea
There was one first-half moment where Chelsea played through a press, found Kante 25 yards from his own goal and when he looked up there wasn't a single red shirt between him and United's back four.
This was another alarming performance from United's midfield and more evidence that it might take more than one summer signing to fix it. United don't just need an elite holding midfielder in the centre of the pitch, they need more brain and more brawn.
Kante, Jorginho and Mason Mount are hardly man-mountains, but they simply overpowered a weak United in the middle of the pitch.
Ronaldo's inspiration
Once Chelsea had taken the lead it felt like this game was over, given the lack of quality United had displayed in the preceding hour at Old Trafford.
They'd struggled to put any pressure on the Chelsea goal and only a tame Fernandes header had tested Edouard Mendy. But when Kante's poor pass was intercepted and the ball fell to Matic, United put together three touches of supreme quality.
The Serbian's loft-wedge of a pass was a thing of beauty, but it was controlled in an instant by a velvet touch from Cristiano Ronaldo, a contrast to the thunderous finish that followed.
At the Emirates on Saturday Ronaldo was more involved in United's build-up play than he had been for a long time. On Thursday there was little build-up play to get involved in, but he showed when the chance arrives there is nobody else you would want on the end of it.
Since Erik ten Hag's appointment has been confirmed Ronaldo has been in fine form in front of goal. He might be 37, but it's hard to see how Ten Hag can build a team that doesn't include Ronaldo next season.
Predictable weaknesses
When Ralph Hasenhuttl outed United's weaknesses in February there was some disappointment at Old Trafford that a coach had been so public in criticism of another team.
Hassenhutl basically made it clear that Southampton's ploy was to outrun a United team who don't like going back towards their own goal. "It is not a big secret that when they lose the ball that the reverse gears are not the best from everybody," he said.
It's become a recurring problem for United that the opposition simply runs further and harder than they do. Almost man-for-man Chelsea's players outworked their United counterparts last night.
It's nowhere more obvious than on the wings. United have struggled against wing-back systems for months and part of the reason for that is their wingers don't like to go back towards their own goal.
Marcos Alonso and, in particular, Reece James just ran the legs off Marcus Rashford and Anthony Elanga. Hasenhuttl's public dissecting of what is essentially an embarrassing weakness is being played on by every opponent now.
Protest
Those United fans who once again occupied the Munich Tunnel in the build-up to kick-off made their protest in a visible way, with the cordite drifting into an eerily quiet stadium in the final quarter of an hour before the game got underway.
If the Glazers were tuning in back in Tampa - and let's be honest, that is far from certain - then they would also have been confronted with a huge 'Glazers Out' banner draped above the tunnel as the players emerged. The letters appeared from nowhere and were in a position where it was impossible for the TV cameras not to pick them up as the teams emerged.
But if those protests were visible, the biggest - and most concerning for the owners - were the empty seats dotted around the stadium. Watching United has been a chore this season and with an unappealing Thursday night, for a team hopelessly out of form and with nothing to play for, plenty chose to stay away, or judging by the number of half-and-half scarves on display, sold their tickets on.
Ten Hag's problems
There is plenty on the pitch to worry Ten Hag ahead of his arrival at Old Trafford, but the latest abject performance came on a day when his task had already been made tougher.
The Dutchman's challenge is to reel in and overhaul Manchester City and Liverpool, but Jurgen Klopp's contract extension to 2026 only makes that harder. There is a sense Pep Guardiola will now follow suit and Ten Hag has a mountain to climb.
He would have seen the departures of Guardiola and Klopp in 2023 and 2024 as staging points for progress, but now he will probably have to rise to their level with those coaches still in post.
It certainly makes the challenge harder, but one thing is for certain. United cannot get any worse than they have been in recent weeks.
Sign up to our United newsletter so you never miss an update from Old Trafford this season.
