PEC Zwolle face the stiffest test of their table-topping credentials yet as they visit reigning Eredivisie champions Ajax on Saturday.
Zwolle have been the surprise package in Holland this year, winning four and drawing one of their first five matches to go two points clear at the summit.
Ajax are five points behind but will be hoping to make a dent in that on Saturday evening at the Amsterdam ArenA.
Their struggles have been on the road, though, with defeat at AZ Alkmaar and back-to-back draws at Heerenveen and Groningen, while they have won both matches on home turf.
Ajax could have captain Siem de Jong back from a bout of pneumonia but he might not play a full game against Zwolle.
The Ajax captain told the club website: "Today or tomorrow we will decide when I can come into action again.
"Maybe I'm already selected for Saturday, but I will not play an entire game. I have to build slowly. It is important that I get match practice."
The other big match of the weekend pits second against third as PSV Eindhoven visit FC Twente.
Phillip Cocu's PSV won their first three matches of the season but were seemingly disrupted by their Champions League play-off against AC Milan.
They drew winnable matches after both legs against Milan, held 1-1 at Heracles and then playing out a goalless home draw with newly-promoted Cambuur.
Cocu will be looking for better after the international break, but would need to break a winless record stretching back eight years at De Grolsch Veste to do so.
AZ host Go Ahead Eagles on Sunday afternoon deflated by the news of Johann Berg Gudmundsson's likely departure.
The 22-year-old has yet to score a league goal this year, although he did score twice at Atromitos in Europa League qualifying and then hit the headlines on international duty last week.
He grabbed a hat-trick for Iceland in the 4-4 draw in Switzerland and seems set for
pastures new in a bid to play more regularly as a central striker.
"I have more to offer," he said.
"I can do a lot more if I'm in the scoring positions. I'm sure I will do more in the right position but it's actually never been discussed due to the presence of first Charlison Benschop and later Roy Beerens (at AZ)."
AZ's director of football Earnest Stewart confirmed: "Johann has indicated he wants to look elsewhere."
Saturday's other matches include Cambuur versus Heracles and ADO Den Haag against Vitesse Arnhem.
On Sunday, Feyenoord visit NEC Nijmegen, Roda JC welcome NAC Breda, RKC Waalwijk head to Utrecht and the division's top-scorer Alfred Finnbogason will attempt to add to his six goals for Heerenveen as they take on Groningen.