United's firepower impresses van Persie

Robin van Persie believes Manchester United's expensively-assembled forward line is capable of frightening opponents.

United manager Louis van Gaal has brought both Radamel Falcao and Angel di Maria to Old Trafford to create an offensive quartet, featuring both van Persie and England's Wayne Rooney, which would be the envy of many a side.

However, United's defensive problems, which have seen it concede 13 goals in seven games so far this season, has limited the impact of its attack.