The Ajax director of football - who played under van Gaal for the Eredivisie side, as well as at Barcelona - is backing his former manager to prove his doubters wrong by bringing success to the Red Devils.
"It's crazy to criticise him so much already," he said.
"In football you need patience. They are building a new team. Yes, they have spent a lot of money, but leave him to do his job.
"He has had difficult times before in his career, but always comes through. He will survive and build a very strong team."
While it was always going to be difficult for United to achieve great success in the years following Sir Alex Ferguson's departure, it is certainly understandable as to why people are questioning whether van Gaal is the right man for the job.
The club sit fourth in the Premier League table currently, however they find themselves six points behind surprise leaders Leicester City, and have a Europa League campaign to look forward to, having fallen at the Champions League group stage.
The disappointment of an unspectacular season is magnified when it is considered that £250m has been spent by van Gaal as he tries to turn United back into title winners (via Telegraph).
And while the club have acquired plenty of young talent with bags of potential - which may be Overmars' argument as to why he foresees van Gaal proving his critics wrong in the future - that kind of investment should surely reap some instant rewards, as well as more long term gains.
But Overmars - who famously swung the momentum of the title race in Arsenal's favour with a winning goal at Old Trafford in 1998 - is certainly backing van Gaal to take United back to the summit of the English game.