Ajax ran riot to signal their title-winning intent with a thumping 6-0 win over Heracles.
Locked in a six-team battle for the crown, the Amsterdam club took over top spot with the win, replacing AZ Alkmaar. Frank de Boer's men are firmly in the mix for the title, with their performance here sending out a clear warning sign to the rest.
They opened the scoring in the first half through Theo Janssen and then cut loose in the second, with Lorenzo Ebecilio, Christian Eriksen, Vurnon Anita, Siem de Jong and Kolbeinn Sigthorsson all finding the net.
AZ Alkmaar ceded top spot as they were held to a 1-1 draw by Europa League hopefuls Vitesse Arnhem at the Gelredome.
The visitors took the lead through American forward Jozy Altidore (32) but Vitesse hit back through Guram Kashia and Marco van Ginkel to forge ahead at the start of the second half.
Simon Poulsen was credited with AZ's equaliser just before the hour mark.
RKC Waalwijk boosted their hopes of clinching a Europa League play-off place with a narrow Eredivisie victory over ADO Den Haag.
Krisztian Nemeth netted the game's only goal midway through the first half to lift RKC back level on points with NEC
The result left ADO, in 15th, only four points clear of third-bottom VVV-Venlo.
De Graafschap remain rooted to the foot of the table after a 2-0 defeat at NEC Nijmegen.
Going into the match two points behind Excelsior, Richard Roelofsen's men knew a three-point haul would lift them off the bottom of the pile. But goals either side of the break from Lasse Schone and Genero Zeefuik ensured that mid-table NEC coasted to a comfortable success, aided by Lion Kaak's dismissal just prior to half-time.