United bounced back from their drab 1-1 draw at West Ham by beating Burnley 3-1 at Old Trafford on Wednesday night.
Chris Smalling scored twice and Robin van Persie converted from the penalty spot late on, but Burnley, who equalised through Danny Ings in the 12th minute, were right in the match and were very unlucky not to take anything from the game.
Van Gaal has received widespread support from the United fan-base since his appointment last summer, but he heard whistles from the home support towards their own team in the first half and that is a worry for the 63-year-old.
"I heard the first whistles," the United boss said.
"That is a concern because we are playing for the fans.
"The fans are the most important part of the club.
"They keep the club living and that is very important but they also applauded after the match and always in matches there is 90 minutes, not 45."
As Van Gaal pointed out, the vast majority of fans cheered their team on for most of the match, which came after the United boss had come in for heavy criticism following the stalemate at West Ham.
Van Gaal's men were branded "long-ball United" by Sam Allardyce following the 1-1 draw.
The Dutchman responded at his press conference on Tuesday by pulling out a four-page dossier filled with statistics and diagrams supposedly undermining the Hammers boss' claims.
Van Gaal's men cut out the long punts up the field against Burnley, but they often lacked any creativity going forward.
Van Gaal admitted the fans, who chanted "4-4-2" at him after he played a three-man defence at QPR last month, deserve better.
When asked if his players looked nervous, Van Gaal said: "Today it was like that, I agree with that so that is a pity because the fans were still supporting, because of the positive (score) at half-time.
"I thought that was fantastic when the team was playing (like) that
I never had that experience with my other teams so I was happy with the support of the teams.
"But of course we cannot have that the next game because then we are out of the FA Cup because we were also lucky today."
Smalling knocked in Radamel Falcao's header just 22 seconds after replacing the injured Phil Jones and he nodded in Angel Di Maria's cross after Ings' flying header had levelled the scores.
But it was only when Van Persie banged his penalty past Tom Heaton in the 82nd minute that the victory, which moved United up to third, was sealed.
"We have to forget this because it was not the best match and for the process it was not good," Van Gaal said.
David de Gea saved from Ings' feet in the second half following a mix-up between Smalling and Herrera.
George Boyd and Michael Keane also went close to scoring for the Clarets.
"I thought we were outstanding," Burnley boss Sean Dyche said.
"Everyone in the stadium is probably scratching their heads how we didn't come away from it with anything."
Part of the reason why United were so slow on the attack was the fact that Wayne Rooney was pushed into a defensive midfield role in the second half after Daley Blind hobbled off following a clash of heads.
Van Gaal brought on Ander Herrera and played him and Di Maria as the middle two players in a diamond midfield, with Rooney sitting behind them.
With United so poor up front, moving Rooney - the third-highest scorer in the club's history - into attack would seem a plausible move, but Van Gaal thinks his team play better with his captain in midfield.
Van Gaal said: "I have to look for the better balance and I think until now because of Rooney we have a better balance in midfield.
"I was very pleased how he replaced Daley Blind in the number six position.
"He showed composure and of course he was also today the Rooney that I want to see but he has showed that he can play in every position.
"Maybe he can better play in a striker's position but then I have a problem in midfield."
Van Gaal said Blind had only suffered a "headache" following an aerial clash and revealed Jones, who lasted less than five minutes on the pitch, suffered a knee injury which will be assessed on Thursday.
"Daley Blind has a headache and maybe tomorrow it is better," Van Gaal said.
"But for Phil Jones, I fear
I don't know
We'll have to wait and see tomorrow."
Source : PA
Source: PA