Former Manchester United captain Gary Neville has described Jose Mourinho's side as lethargic and "inconsistent".
The Red Devils fell further behind the Premier League pace-setters with a goalless draw against Crystal Palace on Saturday afternoon, when the visiting Eagles created the best chances at Old Trafford.
The result means that United have now won four, drawn four and lost four of their last 12 matches across all competitions - a run which includes an away draw with Chelsea and an away win over Juventus, but also defeats to Derby County and West Ham United.
"There's a lethargy, in terms of the fans going into the ground, watching the game, players on the pitch. I think Jose gave the right message before the game saying they will end up in the top four," Neville said on the Gary Neville podcast.
"I don't think it would have been acceptable at the start of the season, and certainly the start of last season, to say the top four is achievable, because he will have wanted to challenge for the title with the money that has been spent. That's where United need to be. But they're not near that level at this moment in time, and it typifies really what they are at the moment, which is inconsistent.
"You can see them go away to Chelsea and nearly win, go away to Watford and Young Boys, and sometimes you can watch them at home against Wolves or Crystal Palace or Valencia, and they're nowhere near. They're inconsistent, not just in games, but from half to half within games.
"It's not right obviously at this moment in time, the players are not performing anywhere near their level. You'd argue Jose at this moment in time will be scratching his head about which players to put out on the pitch. But he's made changes before and it hasn't really made any difference so it's just about battling and fighting away at it, because it is a struggle. I think that's the word to describe it."
United are back in action on Tuesday night when they host Young Boys in a Champions League game at Old Trafford.