Andreas Lasnik inspired the victory as he opened the scoring with a brilliant free-kick before setting up Evgeniy Levchenko to score the winner after Kolbeinn Sigthorsson had brought the visitors level.
The win moved Willem II three points behind second-from-bottom VVV-Venlo, who were denied victory in the late kick-off against Heerenveen by Bas Dost's injury-time strike.
Heerenveen had led until the 85th minute thanks to Mike Vayrynen's strike in first-half injury time before VVV substitute Ruud Boymens struck twice in four minutes to seemingly snatch the points. But Dost had the final say to grab a 2-2 draw and keep the relegation battle alive.
Roda JC took full advantage of AZ's surprise loss as they thrashed NAC Breda 5-1 to keep alive their push for fourth place and Europa League football.
Roda closed the gap to two points as Mads Junker's double was complimented by goals from Jimmy Hempte, Morten Skoubo and Sebastian Svard. Joonas Kolkka scored NAC's only goal.
De Graafschap saw their winless run extended to five matches with a 2-1 defeat at mid-table Heracles Almelo. Everton da Silva opened the scoring for Heracles before the interval with Willy Overtoom adding a second in the final minute.
