Former Manchester United star Viv Anderson has told talkSPORT that unless they improve defensively they could blow their seven point lead in the title race.
The Red Devils current sit top of the pile in the Premier League but have conceded 28 goals, nine more than both Man City and Chelsea, and have let in the first goal in their matches 13 times this campaign.
And Anderson is concerned that they might start being punished for their sloppiness at the back as the season goes on.
“You can’t keep giving decent sides chances like we do,” he told the Weekend Sports Breakfast.
“We got punished against Tottenham not so long ago, so they’ve got to be on their mettle today, especially defensively, and they’ve got to try and keep a clean sheet.
“I think it’s really important that we get back to keeping clean sheets. Good teams who win the league always set themselves up by getting clean sheets week in, week out. We’ve got to get back to that.”