Premier League player of the month Michail Antonio was shown a late red card as West Ham missed the chance to go top of the table after scraping a goalless draw at winless Southampton.
Antonio was dismissed for a second yellow card deep into added time following a late tackle on Moussa Djenepo having earlier been booked for a tangle with Jack Stephens.
Tottenham’s 3-0 defeat at Crystal Palace in Saturday’s lunchtime kick-off had opened the door for the Hammers to climb to the summit with victory at St Mary’s.
But David Moyes’ unbeaten side were lucky to escape with a point as lively Saints substitute Armando Broja struck a post and had a header hacked off the line late on.
Adam Armstrong and Nathan Redmond also had decent openings for Ralph Hasenhuttl’s hosts, who registered a third consecutive draw, while Antonio, Tomas Soucek and Jarrod Bowen had the visitors’ best openings.
With a Europa League campaign to contend with this term, West Ham’s visit to the south coast marked the start of seven games in 23 days.
Hammers boss Moyes resisted temptation to rotate, naming an unchanged starting XI for the fourth successive game and leaving new signings Kurt Zouma, Alex Kral and Nikola Vlasic awaiting debuts from the bench.
United had won six of the past seven meetings but there was little to separate the two sides during a forgettable first half.
West Ham’s lack of attacking threat was surprising given they came into the contest having scored 10 times in their opening three games, a record matched only by champions Manchester City.
In-form Antonio contributed heavily to that statistic with four goals and three assists and he eventually threatened two minutes into the second period.
The away side broke swiftly following a Saints corner, culminating in the 31-year-old – who had a loan spell at St Mary’s 12 seasons ago – stinging the palms of home goalkeeper Alex McCarthy with a low effort which looked set to sneak inside the right post.
That attempt helped inject some much-needed tempo into proceedings.