Former Manchester United defender Danny Higginbotham has said that the Red Devils will continue to struggle as long as head coach Jose Mourinho fails to name a settled centre-back partnership.
United opened their 2018-19 Premier League season with a 2-1 win over Leicester City, but suffered a 3-2 defeat at Brighton & Hove Albion in their second match last weekend.
Eric Bailly and Victor Lindelof have started in central defence in the first two matches, but both struggled against Brighton, and Mourinho is said to be considering changes for Monday's clash with Tottenham Hotspur.
Higginbotham, who played seven times for United, has claimed that the team's defensive problems will continue costing them points this season.
"I think the problem they have is that in [Eric] Bailly and [Victor] Lindelof, they have no consistency," Higginbotham told Sky Sports News.
"We have seen [Chris] Smalling play, we have seen [Phil] Jones play and [Nemanja] Matic play at centre-half and there is no consistent partnership. You look at any successful team, whether it be domestic or international, it's built around a rock-solid centre-back partnership.
"Mourinho, because he hasn't got consistent performing centre-backs he trusts, the players in front who want to go forward and express themselves have an extra defensive responsibility on their shoulders, so they are playing 10-15 yards deeper than they want to. That has a huge knock-on effect on Manchester United going forward."
Mourinho tried and failed to bring a new centre-back to Old Trafford in this summer's transfer window.