AZ saw off lowly VVV-Venlo 2-1 in the the Eredivisie with Jozy Altidore's header settling the contest after Brett Holman had opened the scoring.
Brett Holman had put AZ in front just after the break only for Quin Kruijsen to level.
Ajax closed in on the title with a 2-0 win at home to FC Groningen.
Victory kept the Amsterdam side six points clear of AZ and Feyenoord with three matches to go.
Third-placed Feyenoord claimed a 2-1 success at ADO Den Haag.
Ruben Schaken put the visitor in front just after the restart and
PSV Eindhoven is a point further back in fifth after it came from behind to beat NEC Nijmegen, also 2-1.
Jan Vennegoor of Hesselink scored the winner two minutes from time after