West Ham are currently outside of the relegation zone, but only on goal difference.
Manuel Lanzini has admitted that he and the rest of the West Ham United side have been unable to find a reason for their form at the start of the season but insisted that they should turn things around, the Daily Mail reports.
The season began with plenty of optimism for the Hammers. Slaven Bilic's first season in charge was a success and the move to the London Stadium was deemed to be a massive step in the right direction - despite the club's fans' love for Upton Park.
West Ham United manager Slaven Bilic
However, their form on the pitch has been extremely concerning. Ahead of their game with Manchester United, the Irons are currently situated one place outside of the relegation zone, but are only ahead of Hull City on goal difference. And Lanzini conceded that the team have been unable to put their finger on exactly what has been going wrong.
"It's very difficult to say why," he said, as reported by the Mail. "We have started badly, and that's with no players leaving and more coming in.
Southampton's Cedric Soares in action with West Ham United's Manuel Lanzini
"We've had meetings to analyse things because we couldn't understand what was going on. I think we will progress because we have quality and one of the best players in the Premier League, Dimitri."
Though Lanzini has insisted that West Ham have been unable to work out what is going wrong, their season would perhaps look much better if they were able to hold onto the leads they have held in certain games.
West Ham United's Michail Antonio
They lost to Watford after leading 2-0 back in September, conceded an equaliser against Stoke after going 1-0 up during the second-half and, of course, managed to lose to Tottenham in their most recent game having led 2-1 going into the dying minutes.
Had they held on in those games, West Ham would be on the same number of points as Everton and today's opponents United, who sit seventh and sixth respectively.