Trailing 2-0 in Utrecht after 82 minutes, Ajax looked to have saved themselves when Brian Brobbey and Chuba Akpom netted late goals to level the score.
But Hercules netted the winner through Mats Grotenbreg in the third minute of injury-time after their own coach Rene van der Kooij had given his team a two percent chance of victory before the game.
Ajax coach John van 't Schip was not present to witness his side’s capitulation as he is in Australia to attend his son’s wedding.
It is the first time Ajax have lost to an amateur club in the Dutch Cup. In the 29 previous meetings, they have scored at least four goals.
Ajax spent the early part of this season in the relegation zone but have since risen to fifth in the Eredivisie table, albeit they are a massive 23 points behind leaders PSV Eindhoven.
