Van Gaal was asked repeatedly about De Gea’s future after the game and, although he said the 24-year-old Spaniard would ”not leave us so easily” he appeared braced for such an outcome.

When asked if De Gea was off to Real Madrid, there was no firm rebuttal from Van Gaal, just a list of reasons why he could be tempted to return to his homeland instead.

The United boss said: ”You are asking things I cannot answer because I don’t know.

”I have also said a transfer is an individual thing. It is a process. He has to decide because we have given (him) a fantastic contract because we want him to stay – fantastic season, I think.

”But I analyse his position and then I say he is Spanish, he is a Spanish international and now a Spanish club is coming. His girlfriend is Spanish.”

Madrid dropped first-choice Iker Casillas for their penultimate game of the season on Sunday and his replacement Keylor Navas made a bad error in an eventual 4-1 win over Espanyol.

The result was not enough to prevent Barcelona clinching the title with victory over Atletico Madrid and the rebuilding for next season begins now with De Gea, the former Atletico Madrid man, top of Florentino Perez’s shortlist.

United have already started planning for life without De Gea. Van Gaal drew up a shortlist of potential replacements earlier this year, knowing the Spaniard’s contract expired at the end of next season.

The Dutchman says United have offered their number one “a lot of money” in a bid to persuade him to sign and the fans did their best on Sunday by singing “David de Gea, we want you to stay”.

But Van Gaal conceded: ”I don’t think I can persuade him because he knows everything he has at Manchester United. I don’t have to say something because he can feel it every day. You have seen the fans, unbelievable.

”When he goes he is losing that. Here he has a lot of credits. He has to decide.”

De Gea was fantastic again on Sunday, saving from Aaron Ramsey and his own team-mate Phil Jones. The only time he was beaten was when Theo Walcott’s shot took an unfortunate deflection off Tyler Blackett.

Radamel Falcao waved to all four corners of Old Trafford when he was substituted an hour into his latest sub-par performance.

Van Gaal insisted no decisions had been made about the 29-year-old, who has scored just four goals in 29 appearances since joining on a season-long loan from Monaco.

Van Gaal said: ”You know how the situation is of Falcao. At the end of the season we will decide.”