AZ Alkmaar had to overcame blustery conditions to beat Willem II 2-0 to reclaim third place in the Eredivisie on Saturday.
Feyenoord slipped 20 points behind leaders PSV in Eredivisie after a 2-0 defeat at lowly Heracles on Saturday.
AZ Alkmaar inflicted a second league defeat in four days upon Ajax as they registered a 1-0 win at the Amsterdam ArenA.
Ajax lost 1-0 at Vitesse Arnhem on Sunday to fall further behind PSV in the Eredivisie title race.
Feyenoord beat FC Twente to strengthen their hold of third place in the Eredivisie on Sunday, while Heerenveen won at Utrecht.
The first half of the Eredivisie season concluded with wins for Ajax and Feyenoord, but with PSV hold a four-point lead.