PSV Eindhoven have failed to strengthen their lead at the top of the Eredivisie table, falling to a 1-0 defeat against Heerenveen at Abe Lenstra Stadion.
Jeroen Zoet was called into action early on to deny Daley Sinkgraven's effort, which was heading towards goal before being kept out.
The visitors grew into the contest, and on 27 minutes Florian Jozefzoon came close to finding a way through following some good play down the right, but he could not find an end product.
Heerenveen were reduced to 10 men with 33 minutes played when Stefano Marzo was shown a straight red card, but it took until midway through the second half before they created their next opening, with Jozefzoon only being halted by Kristoffer Nordfeldt.
Joshua Brenet was then shown a red to level the sides up on 67 minutes, and De Superfriezen used it to their advantage by edging ahead through Sinkgraven, who made no mistake when picked out by Luciano Slagveer inside the box.
PSV failed to find a leveller in the remaining time, meaning that they are now level on points with Ajax at the top of the table, while Heerenveen remain in fourth.
