Ajax defeated rivals PSV 2-0 courtesy of an early strike from Kasper Dolberg and a 53rd-minute goal from Daley Blind.
The trio returned to club duty early following their countries' exits in the Round of 16 of the 2019 Africa Cup of Nations.
Onana was involved in the entire 90 minutes and kept a clean sheet while Ziyech was introduced as a substitute for Quincy Promes in the 59th minute.
Mazraoui was an unused substitute for the duration.
Ajax will begin their 2019-20 Eredivisie campaign with a visit to Vitesse on August 3.