PSV Eindhoven have temporarily moved atop the Eredivisie ladder with a convincing 4-0 home victory over Heracles on Saturday, while Ajax suffered their first loss of the season.
PSV are now two points ahead of FC Twente, who face Feyenoord on Sunday, following the rout of their eighth-placed opponents.
Dries Mertens gave the hosts a 19th-minute lead and Luciano Narsingh added a second goal in the 36th minute to help PSV cruise into half-time.
After Kevin Strootman scored PSV's third on 74 minutes, Heracle's night went from bad to worse as Kwame Quansah was given his marching orders before substitute Tim Matavz sealed the win in the 81st minute.
Ajax went into their clash with third-placed Vitesse as the only unbeaten team in the Eredivisie, but with just four wins from their first ten games, they always looked vulnerable against the visitors.
Six draws already this season have pushed Ajax to nine points behind the league leaders, while Vitesse remain on the pace, just one win behind PSV.
Wilfried Bony scored a brace as Vitesse took all three points from the match, leaving Ajax with plenty of work to do ahead of their Champions League meeting with Manchester City on Tuesday.
FC Utrecht capitalised on Ajax's failings, leaping the Amsterdam club into fourth with a 5-1 win over the struggling Willem II.
Cedric van der Gun's 13th-minute opener for Utrecht was countered by an own goal from Jacob Mulenga, but the visitors took charge from the moment Mulenga scored at the right end in the 44th minute to restore their lead.
Substitute Alexander Gerndt netted in the 63rd and 75th minutes, before Mulenga got his name on the score sheet for the third time on the night, his second for Utrecht, with six minutes remaining.
Information from the Press Association was used in this report.