Lasse Schone scored a hat-trick to fire Eredivisie leaders Ajax to a 3-0 win at home to Heerenveen on Sunday.
Schone opened the scoring with a 12th-minute penalty and made it two just six minutes later.
The Dane completed his treble eight minutes from time to move the Amsterdammers four points clear of second-placed FC Twente.
Third-placed Feyenoord's hopes of overhauling Ajax suffered a setback as they were held 1-1 at 10-man NAC Breda.
Darryl Janmaat put the visitors ahead after 25 minutes, but Rydell Poepon levelled from the spot 12 minutes later.
NAC lost Stipe Perica to a red card in the 84th minute, only three minutes after coming on as a substitute, but they held on.
Martijn Barto scored either side of half-time to help Cambuur Leeuwarden beat PEC Zwolle 3-1.
Marcel Ritzmaier put Cambuur 1-0 up before Barto's brace gave them breathing space.
Steve Fernandes Pereira pulled one back 12 minutes from time, but it was no more than a consolation.
FC Groningen beat Go Ahead Eagles's 1-0 thanks to Tjaronn Chery's third-minute goal.