United were so passive you would never have guessed they were playing against a team who hadn't won at home in the Premier League this season.
Mourinho has also had the distraction of a clash with midfielder Paul Pogba having stripped the Frenchman of his role as vice-captain on Tuesday, and seen video footage of a standoff between the pair at training on Wednesday go viral.More news: Sturridge's verdict on sensational strike at Chelsea
West Ham had a couple of opportunities to extend their lead early in the second period, with Marko Arnautovic blazing a volley high and wide at the end of a slick counter, and then being the victim of a poor pass from Anderson who should have teed up the Austrian for a one-on-one.
When play restarted, Rashford cleverly converted from Luke Shaw's corner but Noble picked out the yawning gap between Chris Smalling and McTominay in the United defence and Arnautovic coolly finished the job 16 minutes from time.More news: Kavanaugh accuser Ramirez contacted by FBI: lawyer
However, whenever Romelu Lukaku is on the pitch West Ham have to be wary. Paul Pogba, whose simmering dispute with Mourinho has underlined United's troubles all season, was substituted with 20 minutes remaining after an ineffectual display. And tomorrow he plays. "He is a special personality and a team in a negative moment needs this kind of mentality that Scott McTominay has".
"If I put myself in the position of a journalist, maybe people think that sometimes the boys are not committed, maybe people can think the manager doesn't demand enough from them, maybe people think on the training ground we don't train enough this area or that area".
- Manchester United have scored three Premier League own goals in 2018, more than any other side.More news: Boyfriend Who Filed Restraining Order Against Third Kavanaugh Accuser: 'She's Not Credible'
For much of the second half West Ham played on the counterattack and, when they moved forward, did so with great goal, Anderson especially providing exceptional raking passes. If they can, early-season fears of calamity will feel like a lifetime ago.