Feyenoord's expected tilt at the Dutch Eredivisie title got off to a false start after they went down 2-1 at PEC Zwolle in their opening match of the season.
The visitors from Rotterdam are among the favourites to challenge for top honours this term after finishing third last season, but looked out of sorts today and fell behind to Mateusz Klich's opener in the 65th minute.
Feyenoord looked to have salvaged a point when Ruben Schaken levelled three minutes from the end, but Zwolle had other ideas and claimed all the points when substitute Guyon Fernandez slotted home in stoppage time.
Last year's surprise package Vitesse Arnhem kicked off with a 3-1 win at home to Heracles Almelo.
Vitesse mounted an unlikely challenge last season that only foundered over the final fixtures, but endured a bruising summer with star men Wilfried Bony and Marco van Ginkel leaving for the Premier League.
However, they shrugged off their losses with an assured display today, goals from Kelvin Leerdam (27), Marcus Pedersen (31) and Renato Ibarra (82) sealing a one-sided win before Matthew Amoah pulled one back for Heracles late on.
FC Utrecht and newly-promoted Go Ahead Eagles drew 1-1. Utrecht went ahead through Dave Bulthuis after 15 minutes, but the top-flight new boys levelled through Xander Houtkoop a minute after the restart.
Cambuur Leeuwarden, promoted as Eerste Divisie champions at the end of last season, began their campaign with a goalless draw at home to NAC Breda.