The Dutch giants enjoyed a tremendous 2018-19 campaign, although they've already lost a couple of key players in Matthijs de Ligt and Frenkie de Jong.
Los Blancos have been linked with a possible swoop for Van de Beek after he starred in an attacking midfield berth for the Amsterdam outfit on their way to an Eredivisie and KNVB Cup double.
Ten Hag has said they want to keep the 22-year-old, although it may be difficult, per Marca:
"We will do everything in our power to keep him at Ajax. We don't want to lose him, but when clubs of that calibre enter the situation, things get very difficult.
"Donny was very important for us last season and has started this campaign with enthusiasm, freshness and lots of energy, his departure would be a loss, but we know it can happen."
Van de Beek told Fox Sports (h/t Carlos Forjanes of AS): "Yes, Real Madrid are interested in me. But you go really fast. I can't talk about what there is and isn't."
Per The Spanish Football Podcast, Marca reported that Los Blancos have already agreed terms with the midfielder:
Real Madrid have been busy in the summer window, with Eden Hazard, Luka Jovic, Ferland Mendy and Rodrygo among the big names to arrive. However, midfield remains a portion of the team that's yet to be bolstered.
There have been rumours regarding a possible move for Manchester United's Paul Pogba throughout the summer, but it appears Madrid may have shifted their focus elsewhere.
Van de Beek would be an intriguing signing. The midfielder became renowned for his bursts forward and chipped in with some big goals as Ajax progressed to the UEFA Champions League semi-finals last term:
OptaJohan summed up just how productive the Dutch international has been in the last couple of campaigns:
Van de Beek may not be as technically gifted as a number of players in the Ajax squad, although last season he was frequently the link between midfield and attack.
His passing is snappy, while he regularly makes the right decision on the ball. As his figures show, Van de Beek boasts a composure in dangerous areas that few players of his age can match.
If Madrid were able to get a deal done, his directness and dynamism would help refresh the midfield. While Luka Modric, Toni Kroos and Casemiro have long been an outstanding trio, they all struggled for form at various points last season and would benefit from some overdue competition for their starting place.