Heracles overtook Heerenveen in the Eredivisie table, while Groningen strengthened their European bid at NAC Breda.
Leroy George was the difference between NEC and De Graafschap, and fellow strugglers VVV Venlo and Willem II Tilburg could not be separated.
Heracles moved above Heerenveen in the Eredivisie on Saturday night after a convincing 4-2 victory at the Polman Stadion.
The hosts scored four times in the opening hour - through Everton, Samuel Armenteros, Antoine Van der Linden and Darl Douglas - with Mika Vayrynen and Philip Haglund grabbing Heerenveen's replies.
FC Groningen strengthened their bid for European football next season with a 1-0 victory over NAC .
Andreas Granqvist's 72nd minute strike proved to be the only goal of the game but Groningen also missed a penalty.
Granqvist got the ball inside the area but moved away from goal to make space before unleashing a thunderbolt of a shot.
Groningen had two great chances to add to their lead, but Tim Sparv headed against a post in the 79th minute and moments later Dusan Tadic saw his penalty saved after Jonas Ivens was brought down inside the area by Rob Penders.
Leroy George scored the only goal after two minutes as NEC beat De Graafschap 1-0, and the league's bottom two, VVV Venlo and Willem II Tilburg, drew 0-0.