Louis van Gaal has cast doubt on the idea that he will walk away from Manchester United in 2017 but admits delaying his retirement would be hard on his wife.

Van Gaal insisted on United’s preseason tour that he would leave Old Trafford when his contract expires in 18 months’ time. Sir Alex Ferguson claimed last week that the Dutchman would find it hard to depart, however.

“You never know what Louis will do. When you get the bug it’s hard to leave,” said the former United manager, who reversed his decision to retire in 2003.

There is no suggestion Van Gaal will carry on for a further 10 years as Ferguson did, but there was a slight hint from the Dutchman on Tuesday that his decision to retire is not yet set in stone:

“Normally I shall leave after next year but what is normal in our football world? You never know so I cannot answer that question …

“But I promised my wife to go with her to our paradise (villa in Portugal) so it shall be very hard for me to deny that promise.

“Next year I am 65 and say I stay a year longer, it shall be very hard to my wife.”

Van Gaal has two main objectives before he departs for his luxury villa in Vale do Lobo. He wants to win the Champions League and the Premier League.

He has made a good start on the latter, taking United to the top of the table after seven matches. But United started their group stage campaign with defeat at PSV. Van Gaal believes his men must now win all their home matches, starting with Wednesday’s game versus Wolfsburg, to qualify for the knockout stages.

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“I think in the Champions League you need to win all your home matches otherwise it shall be very difficult,” said van Gaal, who lifted the trophy with Ajax 20 years ago.

Having also won silverware with Barcelona and Bayern Munich, there is certainly no feeling from the United boss that he is not up to the job.

“That is realistic because I did it everywhere,” said the 64-year-old when asked if he could win silverware with United.

“Reaching the (Champions League) final is also an aim and winning the final is a little bit luck.”

Bastian Schweinsteiger, who sat beside van Gaal for Tuesday’s pre-match press conference at Old Trafford, believes United are capable of winning the Champions League.

The German, who won the competition with Bayern Munich in 2013, said: “Yes. I think (we can). But of course first of all we have to do our work.

“As the manager said we have to win our games at home.”

United climbed to the top of the Premier League table for the first time in over two years last weekend when they beat Sunderland 3-0.

The Red Devils have lost once in the league this year, but their performances have been far from outstanding. Van Gaal insists his team are making good progress, however.

“We have made progressions in the maturity and balance of the team,” he added.

“But we need still time to improve because we have to improve.”

Schweinsteiger needs little improvement to his game, according to his manager.

“He is off the pitch very useful and you can see it already,” Van Gaal said.

“He has already (been) accepted as a leading player and that is why we have bought him from Bayern Munich.

“I am very happy with him.”

Schweinsteiger himself is happy to assume the role of mentor to the squad’s young stars like Memphis Depay and Anthony Martial.

“I will try to guide them, of course,” the German said.

“They can achieve a lot.”

Michael Carrick has been ruled out of the game against Wolfsburg through injury.

Ander Herrera and Antonio Valencia also missed the club’s open training session on Tuesday, but could still feature, according to Van Gaal.