Louis van Gaal is adamant that his players will not underestimate Cambridge United during Friday's FA Cup fourth round tie.
The Dutchman has completed his homework on Richard Money's team and has instructed his defenders to expect plenty of long balls at the Abbey Stadium, based on the height of the opposition players.
But having taken note of the Us three consecutive victories in all competitions he is not taking the challenge lightly.
"It is always tough to play against weaker teams because in the players mind, they are thinking it is a weaker team" said van Gaal on Thursday.
"For example, on Wednesday, PSV Eindhoven- the number one in the league in the Netherlands- lost against the number three of the second league.
"It can 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- I have heard that for us we will beat this team easy but I think it is not so easy to beat Cambridge United."
Take a glance at his glittering CV and you will see that van Gaal has won the domestic cup in Netherlands, Spain and Germany.
Although those successes were of greater value to his previous clubs, he feels there is greater emphasis on knockout competitions in England.
"It is different more in the atmosphere, here the FA Cup is very important for the fans, for the people and also for the players. That is the difference.
In Germany, it is fantastic that you win the cup but not like here, and in Spain there are not many matches sold out and that is the difference."