Peter Wisgerhof grabbed the only goal of the game as NEC Nijmegen heaped further misery on PSV Eindhoven.
The reigning Dutch champions were looking to bounce back following their 3-0 Champions League defeat at the hands of Marseille in midweek, but Wisgerhof's strike ensured NEC took all three points.
The hosts took the lead in the 12th minute when Bas Sibum flicked Lasse Schone's corner into the path of Wisgerhof, who volleyed the ball into the left corner from close range.
PSV almost levelled within a minute through Edison Mendez, but home goalkeeper Gabor Babos reacted well to parry the ball out for a corner.
Babos was called into action again after 19 minutes when Balazs Dzsudzsak capitalised on a sloppy pass from Lorenzo Davids before shooting from 15 yards.
Schone then fired over for NEC following excellent work from Rachid Bouaouzan and the Danish midfielder went close again shortly afterwards after an error by Carlos Salcido.
Dzsudzsak almost brought the scores level after 38 minutes with a shot from the edge of the area, but it was NEC who finished the half the stronger, with Youssef El Akchaoui's 25-yard free-kick forcing a fine save from Andreas Isaksson.
PSV struggled to carve out clear-cut chances in the second half, although Serbian forward Danko Lazovic came close to grabbing an equaliser shortly after the hour mark when his long-range effort fizzed wide.
Schone continued to cause problems at the other end of the field and was inches from grabbing a second for the hosts when he slipped the ball wide from an acute angle.
Saidi Ntibazonkiza also saw a shot go close with six minutes remaining, before Lazovic wasted a golden opportunity to snatch a point for PSV when he lifted the ball over the crossbar from eight yards.
The win moves NEC level on 18 points with their fourth-placed opponents, with the duo four points behind leaders NAC Breda, who beat De Graafschap 2-0 last night.
Willem II inflicted more misery on struggling Roda JC with a 2-1 victory.
Two goals from Said Boutahar in the 28th and 75th minutes proved enough for the home side.
Substitute Jeanvion Matondo scored a late consolation for Roda, who slipped to their third successive league defeat.
Heracles Almelo and Vitesse Arnhem played out a goalless draw.