Heracles are top of the Eredivisie after beating reigning champions PSV Eindhoven 2-1 at home.
PSV went ahead early on as Luuk de Jong flicked on a deep free kick in front of Bram Castro, who had come to claim the cross, and into the open goal.
However, Heracles replied with five minutes remaining in the first half with Mark-Jan Fledderus striking the ball from outside the area and past a helpless Jeroen Zoet.
It would not take the hosts long to score a second, after some good passing play saw Thomas Bruns shoot from range, curling the ball home to give his side the lead heading into half time.
Adam Maher was presented with an opportunity straight from the second-half kickoff but the Dutch midfielder's strike was inches wide of the Heracles goal.
Hector Moreno should have put his side level with 10 minutes to go but his tame header landed comfortably in the grasp of Castro.
The hosts held on under intense pressure at the end to go above Ajax into first place while Phillip Cocu's men drop to fifth.
