Jose Mourinho's men have won five on the spin in the Premier League, but this inspired form is yet to see them climb the league table, as those above the Reds continue to pick up points.
The New Years Eve victory over Middlesbrough was a hard-fought contest that needed a late comeback, with goals from Anthony Martial and Paul Pogba sealing the victory in the dying moments of the game.
United haven't tasted defeat since their travel to Fenerbahce in early November, and are unbeaten in the league since the 4-0 drubbing at the hands of Mourinho's former side Chelsea.
United's key players are stepping up to the plate, with Pogba, Henrikh Mkhitaryan and Zlatan Ibrahimovic all turning on the style during United's great run of form.
Unsung heroes Michael Carrick, Ander Herrera and Antonio Valencia are also consistently performing to the top level, allowing the attacking flair of the superstar names to shine through.
Slaven Bilic's side faced off against the Red Devils twice at the end of November, clinching a 1-1 draw in the League, and suffering a 4-1 pounding in the EFL Cup.
Since receiving a 5-1 defeat at home to Arsenal, the Hammers went four games unbeaten through December, including wins over Burnley, Hull and Swansea.
Their resurgence was stopped in its tracks after tasting defeat on New Years Eve against champions Leicester.
This run of form has seen the Irons ease their relegation fears, moving eight points clear of the drop into 14th place; which represents a far worse position than last term.
Captain Mark Noble, as well as Andy Carroll and Michail Antonio have been integral to this run of form, as star man Dimitri Payet didn't scored in a winning effort for the Hammers in December.
Bilic will be hampered by the loss of midfield enforcer Cheikhou Kouyate to the African Cup of Nations.
The Hammers will be hoping for a repeat of the same fixture last time out, as they won a five-goal thriller in the last game ever played at Upton Park.
United will lose Eric Bailly to the African Cup of Nations, just as the Ivorian returned to the team from an injury setback.
Veteran midfielder Michael Carrick is in line for a return after missing the New Years Eve fixture through illness, meaning Marouane Fellaini is likely to drop out.
Phil Jones and Marcos Rojo were rested against Middlesbrough, and are likely to be restored to the side for the trip to London.
Juan Mata impressed coming off the bench, providing the match-winning assist, but will find it difficult to force his way into the front four after such an impressive display, particularly from Pogba and Martial.
35-year-old superstar Ibrahimovic has featured in every league game this season, but is showing no sign of fatigue as his immense goalscoring form was halted by a very harsh decision to disallow his effort at Old Trafford on Saturday.