Ajax are ahead on goal difference from Vitesse, who snatched a last-gasp win at PEC Zwolle on Saturday.
Five away goals ensured fourth place Feyenoord stay four points off the pace as they won a fifth successive league match by beating Utrecht 5-2.
Ajax, who have 40 points, had to deal with a spirited PSV in the first half but took command after the break with the Iceland striker's goal coming in the 65th minute after a break down the flank from Lasse Schone
Three goals in a 15-minute spree in the first half helped Feyenoord come from behind to win at Utrecht.
Jens Toornstra opened the scoring for the home side early but two goals in two minutes from Ruben Schaken and Graziano Pelle put Feyenoord ahead before Toornstra netted again - all inside the first 22 minutes.
Stefan de Vrij scored from a corner to put Feyenoord 3-2 up in 32nd minute and the victory was secured late in the game when Schaken scored again and Tonny Vilhena netted in the last minute.
NEC Nijmegen leapfrogged ADO Den Haag to move off the bottom of the table with a 3-1 win over their relegation rivals.
Marcel Ritzmaier and Martijn Barto scored as SC Cambuur won 2-0 at home to Go Ahead Eagles, moving them to 19 points, one more than NEC and two ahead of Den Haag.