In each group, teams played against each other on a neutral ground. The group winners advanced to the first knockout stage.
Tiebreakers
Teams are ranked according to points (3 points for a win, 1 point for a draw, 0 points for a loss), and if tied on points, the following tiebreaking criteria are applied, in the order given, to determine the rankings:
^ ab"المغرب يستضيف مباريات الدور التمهيدي لكأس محمد السادس للأندية الأبطال" [Morocco set to host Mohammed VI Champions Cup preliminary round fixtures]. uafaac.com (in Arabic). Union of Arab Football Associations. 16 August 2019. Retrieved 16 August 2019.
^"Preliminary Round participating FIFA referees". uafaac.com. 16 August 2019. Retrieved 16 August 2019.