De Jong on song for Ajax
Siem de Jong struck a hat-trick as champions Ajax moved three points clear at the top of the Eredivisie table with a thumping 5-0 win at 10-man Heerenveen.
Ajax cashed in fully after Heerenveen goalkeeper Brian Vandenbussche saw red after just three minutes for hauling down De Jong.
Theo Janssen converted the spot-kick and, after Ismail Aissati scored the second, De Jong bagged his hat-trick to seal a ninth successive league win.
It was also a fifth clean sheet on the spin for Ajax as their lead at the top grew thanks to a 2-2 draw between closest rivals AZ Alkmaar and FC Twente.
Jozy Altidore twice put the hosts ahead at AFAS Stadion but Luuk de Jong cancelled out the early opener before substitute Emir Bajrami's late goal nicked a point for the visitors.
Altidore opened the scoring in the third minute when he headed home an inswinging corner from Maarten Martens before De Jong pulled a goal back on the half hour mark.
Altidore was on target again in the 71st minute but Bajrami - a second-half substitute - headed home Nacer Chadli's left-wing cross to secure a dramatic draw for his side.
PSV Eindhoven's title bid suffered a huge setback as second-half goals from Sander Duits and Mitchell Schet gave RKC Waalwijk a shock win at Mandemakers Stadium.
Jan Vennegoor of Hesselink grabbed a late consolation for the visitors, but it was not enough to prevent Phillip Cocu's men finishing the evening seven points adrift of Ajax.
The result was equally crucial for the hosts, who boosted their chances of reaching the play-off places for a slot in next season's Europa League by moving level on points with eighth-placed NEC Nijmegen.
Feyenoord also dropped points in their title challenge after they drew a blank against Roda JC at the Parkstad Limburg Stadion.
In the other game, NAC Breda remain just five points above the relegation zone after losing 2-1 at home to Heracles Almelo.
The home side took the lead just before the interval through Jordy Buijs, but conceded twice in six second-half minutes.
Ninos Gouriye equalised in the 77th minute before Nemanja Gudelj turned the ball into his own net to put Heracles in front on 83 minutes before he received a red card for an apparent headbutt in the last minute.