West Ham looked really strong, but United's defensive setup was brutal. There were a handful of situations where Shaw/Young were nowhere to be found and Arnautović, Anderson, and Yarmolenko were driving in on United's back line. On Arnautović's goal, he was about 2 yards onside, and still there was nobody within 5 yards of him when Noble hit the through ball.
How much more can United take?
This looked like the proverbial "this team has quit on the manager" game. Not everyone, but Pogba, Shaw, Matic, all were incredibly low energy and effort. The communication at the back was very bad, and maybe some of that is system related, but the biggest thing I noticed in this match was that West Ham's players were working far far harder than anyone on ManU except for Martial and Fellaini.
On the Arnautovic goal.... he harassed the keeper, ManU turned it over, and he drifted back on, into the huge gap caused by the LCB sliding wide because Snodgrass was unmarked, and the RCB who drifted wide because Anderson was unmarked.
The biggest thing though was that Noble wasn't pressured at all, take a look at 0:10 in the video below. It's 4 West Ham players and 6 defenders. Nobody closes down Noble, nobody marks Snodgrass, nobody marks Anderson and nobody marks Arnautovic.
The CBs are hung up in nomans land between Arnie and the wingers, the RB is trotting back, the LB is making a half effort between closing down the passing lane to Snodgrass and closing down Noble, and two midfielders are just standing around between Noble and the backline doing nothing.
That's garbage effort. I mean, if Noble is closed down he probably can't make that pass and at least you force it out wide. The difference in energy and communication was massive all game.
Edit- forgot the video:
0:10 is when Noble hits the pass, somehow 6 United players are between him and the goal, and none of them is marking anyone.