With caretaker boss Fred Grim still at the helm in Amsterdam, Ajax took on the Eredivisie's lowest-scoring team in Excelsior, who scored just 11 goals in their 12 league outings before Saturday and lost four of their last six.
The Amsterdam giants started slowly, creating few chances and refusing to show up in numbers on Excelsior's half. Ajax's passive style kept the lowly visitors alive, especially after Wout Weghorst failed to put the hosts in front following a big chance from inside the box.
Ajax were punished immediately after - midfielder Noah Naujoks was allowed to dribble straight through the heart of the Amsterdam defence and put the ball past Remko Pasveer for a surprising opener.
Naujoks was at it again shortly after the break, calmly placing the ball in Pasveer's bottom corner after youngster Gerald Alders failed to clear a cross.
Ajax were already short on full-backs with Owen Wijndal and Lucas Rosa not fit enough to start in Saturday's game, and the record champions were dealt another tough hand when Danish right-back Anton Gaaei went down with a non-contact injury.
Gaaei's replacement, striker and fellow Dane Kasper Dolberg, got Ajax back in contention with a convincing finish from inside the box, giving Ajax a lifeline for the final 30 minutes.
Excelsior refused to back down, however, as substitute Mike van Duinen got close to restoring the Rotterdam outfit's two-goal cushion. Ajax were kept alive by Pasveer, who finely saved Van Duinen's close-range header.
Ajax tried to crack Excelsior's code and salvage a point from a dire outing, but couldn't come close to beating Stijn van Gassel once as Excelsior booked a sensational win at the Johan Cruyff ArenA - their first in club history.
The Johan Cruyff ArenA will be the stage for Tuesday's UEFA Champions League meeting between Ajax and Benfica, who are ranked 36th and 35th, respectively.
Check out all the player and match statistics from Ajax-Excelsior on Flashscore.
