Ajax's lead at the top of the Eredivisie has been cut to six points after the champions were held to a 1-1 draw by Cambuur Leeuwarden on Sunday.
The Amsterdam outfit came into the weekend with an eight-point cushion at the top but Vitesse Arnhem's win against NAC Breda on Saturday applied the pressure and Frank de Boer's men could not respond.
Siem De Jong gave the home side the lead after just two minutes but Martijn Barto levelled things up after the break to snatch a point for 12th-placed Cambuur.
FC Twente are three points behind Vitesse in third after a Jarchinio Antonia goal just after the half hour saw them beaten 1-0 by Go Ahead Eagles.
Feyenoord trail the Enschede side by a single point after a 2-0 win away at FC Groningen.
Ruben Schaken opened the scoring after 15 minutes and Stefan De Vrij completed a comfortable win four minutes after the break.
In the day's other game, the points were shared in the relegation battle between RKC and ADO Den Haag.
Roland Alberg fired ADO ahead after 17 minutes but Romeo Castelen equalised just before the interval to leave RKC two points behind their opponents in the final relegation play-off spot.