Ajax's Eredivisie title challenge suffered a setback as they relinquished a two-goal lead to draw 2-2 at Roda JC.
Mounir El Hamdaoui missed a penalty two minutes from time which would have restored the visitors' lead in Kerkrade, but it was not to be.
Goals from Miralem Sulejmani and Siem de Jong looked to have set Frank de Boer's side on their way to victory, but Mads Junker got Roda back in the game four minutes before half-time and Anouar Hadouir snatched a point for the hosts with an 82nd-minute equaliser.
Luciano Narsingh scored one goal and set up another as Heerenveen claimed a 2-0 win from a mid-table battle with NAC Breda.
The visitors made the most of a let-off at the start of the second half when Robbert Schilder missed a penalty for NAC, with Narsingh and Oussama Assasi finding the net to earn Heerenveen only their second away win of the Eredivisie season.
NEC Nijmegen extended their unbeaten run to seven games and moved closer to a Europa League play-off spot as two second-half goals from Niki Zimling gave them a routine 2-0 victory over Excelsior.
In the day's final game, De Graafschap played out a 1-1 draw with Groningen.