PSV Eindhoven fired out a warning to the pretenders to their crown with a 3-1 win at AZ Alkmaar, but Ajax extended their lead at the top with a win at Feyenoord.
Ronald Koeman's side have not been able to dominate like in previous seasons, but they overcame a major test on Sunday when ending AZ's unbeaten run.
PSV came out of the blocks at a rate of knots and Manuel da Costa fired them in front on 12 minutes.
AZ failed to fashion a response and two goals in a minute before the break from Edison Mendez and Arouna Kone knocked the stuffing out of the home side.
Demy de Zeeuw netted for AZ 20 minutes from time, but it proved nothing more than a consolation.
AZ's defeat allowed Ajax to extend their lead and they did so in style with a win at Feyenoord.
Feyenoord-Ajax encounters are eagerly anticipated, but this proved a totally one-sided affair.
Klaas Jan Huntelaar increased his stock yet further with a first-half brace and a double from Kenneth Perez completed the scoring.
Feyenoord never really threatened and they ended the game with nine men as Pierre van Hooijdonk and Sebastian Pardo saw red.
ADO Den Haag remain winless after slipping to defeat at Utrecht thanks to goals from Ricky Kruys and Cedric van der Gun.
There was late drama in Nijmegen as Youssef Akchaoui converted an injury-time penalty to lift NEC to a 1-0 win over Vitesse Arnhem.
A hat-trick from Afonso Alves was the catalyst for Heerenveen's 4-2 win over Groningen.