Kluivert was part of Van Gaal's backroom staff when he coached the Netherlands, who he led to the 2014 World Cup semi-finals.
And although he did not follow the tactician to Old Trafford, Kluivert - formerly of Barcelona, Milan and Newcastle United - has watched on with interest.
After embarking on a spending spree that cost United more than £150 million in the close-season - headlined by the acquisition of star winger Angel di Maria - Van Gaal's men have climbed to fourth in the Premier League table.
"He [Van Gaal] came a little bit later from the World Cup and going directly to a new club, with new personnel, new players, it needs time," Kluivert said.
"The last two results were positive and if you have positive results it flows back on the team.
"I think that's the most important thing. So I think the people don't have to be scared that Manchester United is going to not going to do well.
"City and Chelsea and a few more [teams] have a good squad. They're doing very good at the moment but there's still a long way to go.
"But sure [they] can be a contender to be the champions. It will be very difficult but it's possible."
When pressed on his future, Kluivert - who has been linked with a managerial post in England - said his ambition is now "to be a head coach somewhere".
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