Ajax stepped up the pressure on the Eredivisie leaders with a 2-0 win over Groningen on Saturday evening.
Derk Boerrigter put Ajax ahead in the 42nd minute and the game was as good as wrapped up when they were awarded their second penalty of the game in the 53rd minute.
With Siem de Jong having earlier missed from the spot, Lasse Schone this time stepped up to clinch a 2-0 win.
The result leaves Frank de Boer's side level on points with third-placed PSV Eindhoven, who play leaders FC Twente on Sunday. Twente are a point ahead, along with Vitesse Arnhem.
RKC Waalwijk were deserving 2-0 winners against NEC Nijmegen to move up to eighth.
Cuco Martina beat both keeper Gabor Babos and defender Rens van Eijden on the line to open the scoring just before half-time and Florian Jozefzoon took advantage of a stretched defence to exchange passes with Nordin Boukhari and score the second.
RKC went ahead of ADO Den Haag, who were held to a 1-1 draw by PEC Zwolle.
Rochdi Achenteh's free-kick, which flicked off the knee of Joey van den Berg, gave Zwolle the lead in the 24th minute, but Jens Toornstra equalised midway through the second half.
AZ Alkmaar and Willem II drew 0-0 in Saturday's other game.
All the games, like those across the remainder of the weekend, were preceded by a minute's silence in memory of Richard Nieuwenhuizen, the linesman affiliated to youth club Buitenboys who died after being attacked by players from opponents Niuew-Sloten last Sunday.