AZ Alkmaar moved six points clear at the top of the table, while FC Groningen hit Feyenoord for six.
Leaders AZ Alkmaar strengthened their grip at the top of the table with a hard-fought 1-0 win at Heracles.
Adam Maher popped up with the winner a minute from time to send AZ six points clear of PSV Eindhoven.
FC Groningen stunned Feyenoord with a thumping 6-0 win over the Rotterdam outfit.
The home side got off to a flying start with Dusan Tadic firing them in front in the very first minute and Maikel Kieftenbeld and Petter Andersson added two more inside the opening 20 minutes.
Leandro Bacuna made it 4-0 for Groningen ten minutes after the break and things got worse for Feyenoord when Dani Fernandez was sent off on 64 minutes.
Virgil van Dijk and substitute Suk Hyun-Jun completed the rout with two goals in the closing stages.
NEC Nijmegen climbed out of the drop zone with a 3-1 victory over Utrecht.
Lasse Schone set NEC on their way with the opener after just three minutes and Leroy George doubled the advantage ten minutes later.
NEC were gifted a third goal 15 minutes from time when Utrecht goalkeeper Roberto Junior Fernandez scored an unfortunate own goal.
Jacob Mulenga netted a late consolation for Utrecht from the penalty spot, but it was too little too late for the visitors.
Vitesse Arnhem boosted their European aspirations with a narrow 1-0 win over struggling De Graafschap.
Wilfried Bony scored the only goal of the game 20 minutes from time to move Vitesse above Ajax in the table and increase De Graafschap's problems at the wrong end of the table.