#2 Lack of squad depth and rest
Due to a profound lack of squad depth this season, the Real Madrid players have had little chance to rest and Santiago Solari has opted for almost no rotations in February. The poor form of Marcelo, Bale, Mariano, and the rest saw the likes of Karim Benzema, Vinicius Junior, Luka Modric, Sergio Ramos, and Reguilon playing almost every game in the past month.
Moreover, Ajax played their last game almost a week ago, whereas Real Madrid faced Barcelona this weekend, three days prior to their crucial test against Ajax. It is crystal clear that Ajax's players will be fresher and hungrier as they face Real Madrid tonight.
Moreover, it would not be wise for Santiago Solari to experiment with his squad despite a lead and two away goals, due to the threat posed by this Ajax team. Unlike Real Madrid, this team is young and will be ready to give it their all for 90 minutes and more, if needed.