AZ Alkmaar established a three-point lead at the top of the Eredivisie table on a day when two of their main title rivals suffered surprise defeats.
AZ saw off lowly De Graafschap 2-0 following second-half goals from Rasmus Elm and Erik Falkenburg, and there was further good news elsewhere for Gertjan Verbeek's men as PSV Eindhoven and FC Twente both lost 3-1 at teams in the bottom half of the table.
PSV's miserable recent run continued as they lost their third successive league match after going down to NAC Breda in a game that saw both teams finish with 10 men.
Despite taking an early lead through Georginio Wijnaldum, PSV conceded quick goals from Santi Kolk and Anthony Lurling.
PSV then lost Stanislav Manolev to a red card and NAC took advantage with another goal from Kolk after the interval.
The dismissal of Robbert Schilder evened up the numbers but there was no way back for PSV, who slip to fourth spot on 48 points - the same as FC Twente, who were beaten by NEC Nijmegen.
Twente had thrashed PSV 6-2 away last weekend but they were left to rue a 15-minute period either side of half-time when NEC took control of the match.
Lasse Schone opened the scoring from the penalty spot in the 44th minute and goals from Kevin Conboy (50) and Genero Zeefuik (59) put the hosts three up.
Glynor Plet pulled one back for the visitors 13 minutes from time, but it was too little too late.
Also taking advantage of the defeats for PSV and Twente, in-form defending champions Ajax moved into second place on 49 points - three behind AZ - with a 3-0 home win over RKC Waalwijk.
Jan Vertonghen, Siem de Jong and Lorenzo Ebecilio struck the goals as Ajax recorded their fifth successive league victory, during which run they have outscored their opponents by a combined 17-3.
There was another unexpected result in today's other Eredivisie match, with sixth-placed Feyenoord held 1-1 at home by fourth-bottom FC Utrecht.
Feyenoord took a sixth-minute lead through Otman Bakkal but they were pegged back by Cedric van der Gun's 59th-minute equaliser and were then forced to hold on for the final 14 minutes with a man less following Miquel Nelom's dismissal.