PSV were surprisingly beaten by Heerenveen, but Ajax made no such mistake as they brushed aside PEC Zwolle 3-0 at the Amsterdam ArenA.
Kolbeinn Sigthorsson and Siem de Jong put the hosts two up inside 26 minutes before Derk Boerrigter added the gloss late on.
Feyenoord and Vitesse Arnhem, the sides in third and fourth, both celebrated 1-0 away wins.
Graziano Pelle's goal on the half-hour saw off Roda JC for Feyenoord, while Wilfried Bony netted in the 63rd-minute as Vitesse edged out FC Twente.
Utrecht also secured a 1-0 success, Jacob Mulenga notching 12 minutes from time to down visiting RKC Waalwijk.