Goals from Juan Mata and Zlatan Ibrahimovic ensured United extended their winning run to six in the Premier League, further closing the gap to the top four.
The game was marred by a poor showing from referee Mike Dean, after he controversially sent off Hammers winger Sofiane Feghouli, and failed to rule out United's second goal, despite Ibrahimovic being in an offside position.
Goalkeeper - David de Gea - 9: United's ever reliable keeper came up with the goods once more to deny the Hammers; marking his 250th United appearance with a clean sheet. De Gea made some stunning saves to deny West Ham attackers Manuel Lanzini on two separate occasions, and a one-on-one opportunity for Michail Antonio.
Right-back - Antonio Valencia - 7: One of United's most consistent performers this year continued his good vain of form. His strength and pace going forward has now been joined by a sound defensive brain that has solved a potential right-back problem for Jose Mourinho. Valencia was helped by the loss of one of the Hammers' wingers early on, which often left him with just attacking to do. He missed a guilt-edged chance before half-time from within 10 yards, but was a dangerous attacking weapon for United.
Centre-back - Phil Jones - 8: Having been rested for the New Years Eve fixture, Jones returned and was in the thick of the action. His clash with Feghouli saw the Algerian dismissed, which earned Jones the hatred of the London Stadium crowd for the duration of the game. Jones was rarely tested as the Irons didn't field a recognised striker.
Centre-back - Marcos Rojo - 7: Rojo enjoyed a quiet first half at centre-back, but switched to left-back after the break. The Argentinian, despite playing the World Cup final at full-back, has consistently looked less comfortable out wide, and this was the case against West Ham. His attacking work needs improvement if he is to develop into a solid full-back option for Mourinho.
Left-back - Matteo Darmian - 5: The Italian was hauled off at half-time after an underwhelming first 45 minutes. He simply didn't get forward enough to expose a vulnerable Hammers side, still reeling from the early red card.
Centre-midfielder - Michael Carrick - 8: Selecting Carrick is a free ticket to avoiding defeat for Mourinho. When he's started, United are unbeaten. The veteran midfielder was not at his best for large parts of the game, often lying too deep to create chances or help the other midfielders to flourish. However, his class and quality shone through to help United to a lead. A wonderfully weighted ball out to substiute Rashford lead to the first United strike, and the eventual win.
Centre-midfielder - Ander Herrera - 6: Herrera was one of the least influential for the Red Devils, as the passive Hammers midfield didn't need to be disrupted by the stellar break-up play from the Spaniard. The deep-lying United midfield meant Herrera struggled to create chances, not enjoying the very compact Irons layout after the Feghouli red card.
Centre-midfielder - Paul Pogba - 8: The Frenchman oozed class at the London Stadium, displaying incredible skill and trickery to beat opposition defenders. He was frequently too deep, along with the whole United side, but that gave him the chance to display his solid defensive ability. His passing range and physicality meant he could control the game.
Right-winger - Henrikh Mkhitaryan - 5: The Armenian put in his worst performance for United since his reinstatement to the side. He sat too deep for the majority of his time on the pitch, not making the deadly runs that his seen him in such lethal form for the Red Devils. His lack of involvement in the game saw him replaced by Smalling once United took the lead.
Left-winger - Jesse Lingard - 4: Similarly to Mkhitaryan, Lingard put in a lacklustre performance. His lack of movement and penetration meant United only had one attacking option; go through the middle. The Hammers figured this out and neutralised the attack by congesting the middle of the park. Lingard seldom attacked defenders and didn't threaten to run past them, unlike Anthony Martial during his man of the match display against Middlesbrough, which strangely saw him drop to the bench.
Striker - Zlatan Ibrahimovic - 7: Ibrahimovic notched up 50 goals in 2016, and started the new year like he ended the last one, with a goal. Despite a generally poor game for the Swede, often isolated and miscontrolling the ball, as well as being caught offside, he took the chance he got; the clinical nature which means he's still one of the world's best. Despite being in an offside position, Ibrahimovic tucked away his opportunity in a ruthless manner, making up for the goal he should have had against Middlesbrough.
Juan Mata - 8: Mourinho's substitutions changed the game, and Mata was integral to that. A stunning finish from a Rashford pass gave United a deserved lead and sent them on their way to a sixth consecutive victory. The Spaniard was good for United with intricate passing to unravel the very tight Hammers defence.
Marcus Rashford - 9: Rashford provided United with everything Mkhitaryan and Lingard didn't. His frightening pace and willingness to take on the Hammers full-backs lead to United's goal. The England starlet breezed past Havard Nordtveit to deliver to Mata for United's goal. His pace on the counter attack was too hot to handle for Slaven Bilic's men.
Chris Smalling - 6: Vice-captain Smalling came on to balance the side after the attacking half-time substitution saw Mata replace Darmian. The demoralised Hammers offered very little in attack once they had fallen behind.