Louis van Gaal insists David De Gea will not leave Manchester United before the transfer window shuts.

De Gea will once again be in the stands when United take on Newcastle at Old Trafford on Saturday because Van Gaal feels the Spaniard is still not able to focus properly because of Real Madrid's interest in him.

According to reports in Spain, the 10-time European champions will make one last attempt to sign the goalkeeper before the window shuts on September 1.

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But after a week in which United's reputation took a blow following Pedro's move to Chelsea, Van Gaal came out fighting at his pre-match press conference on Friday.

The Dutchman insists the lure of Manchester United remains as strong as their desire to hold on to their two-time player of the year.

"I think when Manchester United wants a player he shall come, besides when a club is not selling," the United manager said.

"It is the same with us. We are not selling De Gea."

Despite bristling at constant questioning regarding Pedro, Van Gaal suggested he is not too disheartened at failing to sign the forward, and claimed he would be happy to go through to the new year with the squad he currently has.

When asked whether there would be any more signings before the transfer window shuts, Van Gaal said: "You have to wait to see.

"It's not any pressure for me. We have 28 players. We did it last season without Pedro.

"When it is like that, I go with this squad because we have 28 players and I have said already now we have a better balanced selection.

"When we buy it has to be a contribution to our selection and it has to be not against any price."

Van Gaal said he would not speak publicly on Southampton winger Sadio Mane as he did not want to "interfere" with the club's pursuit of the Senegalese.

He added: "I cannot answer that question neither because I cannot interfere. I don't want to interfere. It's for Ed Woodward doing the things and he does it very well, I think."

If history is anything to go by, Van Gaal will be able to rely on one of his current crop to find the goals against Newcastle on Saturday.

Wayne Rooney has scored 11 goals in 17 Premier League starts for United against the Magpies.

The United skipper, who is yet to find the net this year, admitted in midweek his performance in the 1-0 win over Aston Villa was not good enough.

Van Gaal was encouraged to see honesty from his captain, and backed him to hit form soon.

"When you are saying so publicly that you are so bad then you know you are very bad at that time," Van Gaal said.

"I think it's fantastic that a player admits that. For me it's unbelievable because he is one of a few players saying such things.

"He is taking a risk, but he is very confident that he shall make the goals we expect from him and I am confident also."