Manchester United boss Louis van Gaal complained "every aspect" of the match went against his team after Cambridge deservedly earned a FA Cup fourth-round replay at Old Trafford.

Van Gaal and his distinguished visiting side endured an uncomfortable evening at the R Costings Abbey Stadium in a goalless draw which will live long in the memory for Cambridge, the lowest ranked side remaining in the competition.

"Every aspect of the match is against us," Van Gaal said.

"We have to come here, the pitch is not so good, but that can influence also that you play in another playing style.

"The opponents are always giving a lot more than normal. And defending is always easier than attacking.

"Then you have seen the referee (Chris Foy). It's always the same. Everywhere I have coached these games – and I have coached them also with other clubs – it's always the same."

Van Gaal refused to expand on his appraisal of Foy, but was critical of his side's first-half showing, believing they played Cambridge's game, rather than their own.

He added: "We made the same error as against Yeovil Town and against QPR, that we played in the same playing style as the opponent and that we don't have to do.

"It was a pity we had to wait again till half-time, but I the second half I was pleased.

"We didn't score and I have to give also the credit to this club, of course, because Cambridge United played very well, very well organized, with the heart. They have fought till the end.

"We are still in the cup and that's the most important thing. I've seen lots of times big clubs losing against such opponents."

Josh Coulson might have scored following pin-ball in the United box in the first half, while Chris Dunn saved from substitute Robin van Persie and Angel di Maria in quick succession to earn a replay in Manchester which will provide a major financial boost for the Us.

Asked if he thought Cambridge, promoted to League Two last season after nine years in non-League football, can go to Old Trafford and win, head coach Richard Money said: "No. I don't, but you never know.

"We've said in the dressing room you're going to Old Trafford. Who cares what happens? Just go and enjoy it, soak it in. Whatever happens, happens.

"(It is) difficult to put into words just how proud we are. When you get back in the dressing room and recover, you just suddenly start to think about what it means to so many people.

"This club has been in the doldrums for 10 years, out of the Football League, and suddenly here we are taking everybody back to Old Trafford. It's incredible."

Money thought his side gave a good account of themselves and that it was scripted that substitute Luke Chadwick would score against his former club.

"We knew that they'd have a lot of the ball, but I thought in the first half we pinched it a few times and looked dangerous," Money added.

"Second half we've shown all the character, all the courage. There were one or two little thrills and spills and you thought maybe the game was made for Chadwick to find something.

"I suppose he was more intent on getting back to Old Trafford."

Money said earlier in the week that his players would have to pay for a new shirt if they swapped with their opponents.

"Not one player asked me (if they could swap)," Money added.

"We might buy them one now, though."

Dutchman Van Gaal said a 4-4-2 formation gave him a "twitchy a**" but selected four at the back due to it resulting in more chances.

Van Gaal added: "I know the statistics of our former performances. You could see we create more chances (playing 4-4-2).

"(But) it is not only the system. It is also the performance of the system.

"It is not so easy to change the system or something. That is not the solution. That I know."

Van Gaal rested Wayne Rooney and Juan Mata, but did not rue the decision with hindsight.

"I'm not regretting that," he said.

Mobile app users, watch the video interview.