- Referee Mike Dean widely criticised after sending off Sofiane Feghouli inside 15 minutes following 50-50 challenge with Phil Jones.
- Zlatan Ibrahimovic appeared to be stood in an offside position as he hammered home United's second after 78 minutes.
- Juan Mata opened the scoring after 63 minutes with Marcus Rashford providing the assist having come off the bench in the second-half.
Six wins in six for Jose Mourinho's side; they are now just a point off the Champions League places.
Full-time: West Ham United 0-2 Manchester United
The London Stadium is practically empty already.
Ibrahimovic stands over the free kick but can only hammer it into the wall.
United are cruising towards the final whistle here; they now have a free kick on the edge of the box after Ibrahimovic's dinked pass is deliberately handled by Reid.
United almost have a third! Rashford has been sensational since coming off the bench, he again comes in from the left and stands a superb ball up for Herrera who is breaking into the box. He volleys on goal, but Randolph gets down well to keep it out.
United have their second, but it is another very poor decision. It's a sweet connection from Ibrahimovic as he hammers past Randolph, but he was stood offside when the ball broke to him. Even Zlatan knew it, immediately looking across to the linesman as the ball hit the back of the net but the flag stayed down.
Goal! West Ham United 0-2 Manchester United (Zlatan Ibrahimovic, 76)
On the break, Ibrahimovic threads a ball through for Rashford who has little choice but to his a shot first time. It's a comfortable save for Randolph, but he then lets it squirm through behind him, rolling off the inside of the post!
Valencia comes crashing through the back of Carroll and picks up a yellow card for himself.
A whisker away from Pogba! Rashford again makes an intelligent run from the left in behind Nordtveit and cuts the ball back precisely for Pogba. He opens his body up and tries to steer it into the far corner, but it veers just wide of the West Ham goal.
It;s a poor delivery however, easily cleared at the first time of asking.
West Ham have their first chance to launch one into the box with Carroll in there after Carrick is penalised.
Now Slaven Bilic makes a change, Payet trots off to be replaced by Andy Carroll.
Pogba lets the ball run across his body and looks to guide one into the far corner, sending Randolph scrambling across goal but his effort is always veering just wide.
After that goal, Mourinho makes his final change with Chris Smalling coming on for Mkhitaryan. Carrick will move back into midfield.
United finally have their breakthrough! Moments after Antonio passed up the best chance of the game, West Ham are punished. Carrick lifts a superb ball out for Rashford, who drives in from the left with Nordtveit backpeddling. The 19-year-old reaches the byline and superbly picks out Mata, who steers it into the far corner.
Goal! West Ham United 0-1 Manchester United (Juan Mata, 62)
De Gea saves again! West Ham cut through United with ease with the away side's line all over the place. Lanzini slides an easy one through for Antonio who is one on one with De Gea, but he makes a vital stop with his legs.
Here comes that change. Jesse Lingard, who has been very ineffective this evening, trots off to be replaced my Marcus Rashford. Anthony Martial remains on the bench.
Marcus Rashford looks like he might be the next man to come on.
A pass rebounds off Mike Dean and into the path of Mkhitayran, who is cleaned out by an awful challenge from Kouyate. It should be a yellow, but the West Ham man gets away from it.
Ibrahimovic now almost latches onto the end of a dodgy back pass but Randolph races off his line to sweep clear.
United do look a lot sharper, zipping the ball down the left before it is swung into the box. Valencia knocks the ball back to the edge of the box where Ibrahimovic allows it to run to Lingard, who curls his shot well over the bar.