Manchester United's centre-back pairing of Harry Maguire and Victor Lindelof makes Rio Ferdinand 'fear for his life'.
The former Red Devils defender isn't convinced by the partnership, which has been picked apart in the Premier League this season.
Manchester United's defence was poor on the opening day defeat by Crystal Palace, with Maguire and Lindelof's lack of pace a growing concern.
And Champions League winner Ferdinand believes changes must be made if the Red Devils are going to start lifting trophies again.
Ferdinand told BT Sport: "Is it good enough? I'd probably say no, if you're trying to win the top competitions.
"Yes, last season they had a good defensive record, but I just see moments in games where they get opened up.
"They get physically dominated at times, especially in terms of pace, especially if their protection isn't what you'd expect it to be if the game opens up a little bit.
"If the game opens up and they're on the halfway line and they're playing 1v1 or 2v2, then I fear for my life in that situation.
"If the team shape is fine and it's all set up properly, then they look a decent pairing."
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