AZ Alkmaar tightened their grip on the Eredivisie trophy as they extended their lead to nine points with victory at Sparta Rotterdam.
With Ajax losing to Heerenveen, AZ capitalised with a convincing win courtesy of second-half goals from Moussa Dembele and Mounir El Hamdaoui, maintaining their 100% start to 2009.
PSV Eindhoven ended a difficult weekend on a high note with a resounding victory at lowly De Graafschap.
PSV caretaker boss Dwight Lodeweges took charge for the first time following the resignation of Huub Stevens on Wednesday, and could not have asked for a better start.
A goal in each half from Ibrahim Afellay and an Ola Toivonen strike handed three easy points to the reigning four-time champions, although PSV remain well off the pace in the title race and stay fifth, 15 points behind leaders AZ Alkmaar.
Milano Koenders' last-gasp goal gave NEC Nijmegen a narrow win over Feyenoord, whose dismal away record continues.
Koenders headed home in stoppage time to give Mario Been's side victory over the team he is set to join in the summer.
Feyenoord's troubles continue under interim coach Leon Vlemmings as their seventh away loss leaves them 12th in a tightly packed bottom half of the Eredivisie table.
Elsewhere, FC Twente's title challenge faltered as they were held to a goalless draw at FC Utrecht.