Siem de Jong had them ahead inside four minutes, before a second-half brace from Lerin Duarte and a further strike via Ricardo Krishna made the scoreline more emphatic.
Ajax profited from a 2-2 draw between two of their title rivals, FC Twente and Feyenoord at De Grolsch Veste in Enschede.
It might have been worse for second-placed Twente but they rescued a point when Rhuendly Martina scored in the fifth minute of added time.
The visitors held a two-goal lead through Graziano Pelle and Jean-Paul Boetius, but Luc Castaignos pulled one back midway through the second half.
Vitesse moved into third one point above Feyenoord with a 3-1 home win over RKC Waalwijk that leaves them eight points behind Ajax.
Mike Havenaar, Valeri Kazaishvili and Christian Atsu scored their goals in the second half after they had fallen behind in the first half to a Kenny Anderson strike
Utrecht eased their relegation worries with a 1-0 win over Groningen courtesy of a late strike from Johan Martensson.
- Sports & Recreation
- FC Twente
- De Grolsch Veste