Davinson Sanchez and Kasper Dolberg both scored twice as Ajax beat Zwolle 5-1 while PSV won at Excelsior.
Eric Botteghin struck a late winner as Feyenoord maintained their perfect start to the Eredivisie season with a 1-0 win at PSV.
Dundalk manager Stephen Kenny admits his side are seen as outsiders as they prepare to face AZ Alkmaar in the Europa League.
Luuk de Jong capped a 24-minute blitz as PSV stormed back to the top of the Eredivisie with a 4-1 win over NEC in Nijmegen.
Hull have signed AZ Alkmaar's Norway international Markus Henriksen on a season-long loan.
PSV Eindhoven surrendered their 100 per cent record in disappointing fashion after being held to a 0-0 draw at home to Groningen.