Edouard Duplan scored twice Sunday to give FC Utrecht a 3-0 win over Ajax, handing new coach Frank de Boer his first Dutch league defeat.
Ajax stayed third with 38 points but lost ground to league leader PSV Eindhoven, which beat VVV-Venlo 3-0. PSV has 44 points, one more than defending champion FC Twente, which dismissed FC Groningen 2-1.
Wilfred Bouma, Jeremain Lens and Atiba Hutchinson each scored in PSV's win at struggling VVV while Marc Janko netted in each half in Twente's comeback win. The lanky Austria forward missed a penalty in the 84th.
Tim Matavz had given Groningen a 33rd-minute lead.
After a commanding start, Duplan fired Utrecht ahead from a long-range shot in the 22nd and beat leftback Daley Blind to a Kevin Strootman cross on the far post a minute later to double his tally.
Ajax captain Marteen Stekelenburg twice made diving saves in the first half to keep out Frank Demouge's efforts as Utrecht continued to dominate possession.
"It was really frustrating to see how most of my players underperformed today," said De Boer, a former Ajax and Netherlands defender, who replaced Martin Jol as coach late last year.
Miralem Sulejmani missed Ajax's solitary chance of the game when his shot went wide, two minutes after the break.
Ismo Vorstermans scored the third, converting Michael Silberbauer's cross in the 82rd.
Also Sunday, Jimmy Hempte, Pa Modou Kah, Morten Skoubo were on target as Roda JC beat Exelsior Rotterdam 3-0.
On Saturday, Leon Broekhof's 88th minute goal helped De Graafschap to a 1-0 win at Feyenoord while Willem II ended a 19-game winless streak, edging Vitesse 1-0 for its first win of the season thanks to Rangelo Janga's 26th-minute effort.
Heracles Almelo held AZ Alkmaar to a 0-0 draw and NEC also earned a point against NAC Breda after a 2-2 draw Saturday.
