They poached Daley Blind from the Eredivisie outfit back in the summer transfer window of 2014, when Van Gaal was boss.
And they then negotiated a return for the Netherlands international four years later after he was deemed surplus to requirements by Mourinho, who was manager at the time.
In 2020, United snapped up Donny van de Beek – paying a fee in the region of £40million to bring the midfielder in.
Van der Sar, who spent six glittering years at Old Trafford during his playing days, was personally involved in the negotiations.
And it now seems only a matter of time before Ten Hag moves to the Premier League, even though the club plan on talking with other candidates including Mauricio Pochettino, Julen Lopetegui and Luis Enrique.