Louis van Gaal has admitted he has some concerns over the mentality of his players as they approach today’s game against League Two side Cambridge.

However, the fact he has stressed the importance of not underestimating the opposition will hopefully mean the players take heed.

It’s always tough to play against weaker teams because in the players’ minds, it is a weaker team. For example, on Wednesday, PSV Eindhoven – who are no.1 in the league in the Netherlands – lost against no.3 of the second division. It shall happen also in the FA Cup. There are always surprises and I hope we are not the surprise. When you see Cambridge and when you analyse Cambridge, they play very direct with long balls. They have five or six players who are taller than 1 metre 90 so for us it will be difficult to defend against. That is why you have to prepare yourself very good. It is not so easy to beat Cambridge United.