The 62-year-old, who will take charge after the World Cup, has again said how he was in line to manage the club 12 years ago before the Scot opted against retirement
The Netherlands coach was confirmed as David Moyes's permanent replacement on Monday, penning a three-year deal which will begin after his World Cup commitments.
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"I was going to replace him in 2002, when he wanted to quit," he told Dutch television. "But in the end he came back."
Former Under and Scotland defender Gordon McQueen told Goal earlier on Monday that he is "not sure" if Van Gaal is the right man for the club, stating that his relationship with Ferguson will be crucial.
But Van Gaal insists there will be no pressure with the former boss attending matches, and insisted two have a good relationship: "I don't think it's a big problem, I put more pressure on myself than others do.
"I'll undoubtedly have a drink with Ferguson. We’ve done that before. We like each other."
United suffered their worst ever Premier League season under Moyes, and Van Gaal acknowledged the need to improve results quickly in his new role.
"United is the biggest club in the world. Marketing-wise, but also if you look at their budget. They have to finish high [up the league].
"The aim is to bring them back to the No.1 position as soon as possible, because that’s where they were under Sir Alex Ferguson. It's going to be a difficult job but it is a fantastic challenge.
"It was retirement, or going to England. My wife Truus wanted me to retire. But now we're going to England.
"I told [Woodward] my vision, who I wanted on my staff and what I wanted for the future. He was impressed.
"I didn't call Manchester United, I didn't call Bayern Munich, they've always called me. And I'm proud of that."