Manchester United manager Sir Alex Ferguson believes that the Red Devils could be in danger of losing to their fierce rivals Manchester City this weekend if they fail to tighten up their defence.
The North-West outfit currently sit at the top of the Premier League table but have been conceding goals regularly and Ferguson has expressed concern ahead of the Manchester derby.
"[Defeating Man City would be] one of our best ever results," BBC Sport quotes Ferguson as saying. "It won't be easy and if we defend like we did at Reading we'll be in trouble."
United managed to edge a 4-3 victory over Reading last Saturday.
