United were forced to settle for a fourth consecutive home league draw as Jose Mourinho was sent to the stands for the second time in a month.
The boss received his marching orders for kicking a water bottle after Paul Pogba was booked for taking a tumble - replays showed there was no contact in his clash with Mark Noble.
He also received his marching orders in the game against Burnley and, like that encounter, this proved to be another afternoon of frustration at Old Trafford.
Diafra Sakho put the struggling Hammers ahead inside two minutes but, after Zlatan Ibrahimovic equalised, the Reds, not for the first time this season, found the visiting goalkeeper in fine form.
Darren Randolph made a series of fine stops to keep out Jesse Lingard, Marcus Rashford, Paul Pogba and substitute Henrikh Mkhitaryan to earn his side a precious point.
With Slaven Bilic's side also the opposition in Wednesday's League Cup quarter-final, the Reds knew that there was crucial physiological advantage, as well as league points, to be gained with victory.
Instead, we got off to a nightmare start when a trademark Dimitri Payet free-kick was met by Sakho, who muscled past Ibrahimovic to power home his header.
United were level with their first real opening when Pogba's pinpoint pass picked out Ibrahimovic who nodded past Randolph from close range.
Mourinho was then sent to the stands for his passionate reaction to a coming-together between the French midfielder and Hammers captain Mark Noble.
Lingard volleyed over on the stretch and Marcus Rashford should have done better when one-on-one with Randolph.
The unmarked Zlatan then had a shot blocked when well-placed and Randolph saved well from Lingard after Juan Mata had played him in shortly before the break.
The visitors started brightly after the restart and - after Sakho went close with another header - the Reds needed a superb save from David de Gea to keep out another Payet set-piece.
Mkhitaryan again impressed after his introduction in place of Mata, and the Armenian was quickly in the thick of action.
The Armenian fired against the post but Lingard's follow-up was ruled offside, before Randolph saved well from Pogba's well-hit effort from distance.
The Hammers keeper was called into action again soon after when substitute Rooney found Ibra only for Randolph to block well with his foot.
Former United Academy graduate Ashley Fletcher almost stole an unlikely victory for the visitors, and Rooney fired wide late on, but there was to be no twist in the tale.
Overall team performance: 6/10
United Faithful Man of the Match: Paul Pogba