Napoli made it three wins out of three for Italian sides in the Europa League on Thursday night with a 2-0 victory at Legia Warsaw.
There were Eredivisie wins for both Ajax and PSV on Saturday, while second-placed Heracles slipped to defeat.
Ajax returned to the top of the Eredivisie with a 2-0 victory over Excelsior on Sunday.
Ajax's Anwar El Ghazi scored twice in a 4-0 win over ADO Den Haag that took them clear at the top of the Dutch league on Sunday.
There were wins for Ajax and Feyenoord in the Eredivisie on Sunday, while FC Twente slipped to defeat.
Ajax started their Eredivisie campaign with victory over AZ Alkmaar, while Willem II and Vitesse played out a 1-1 draw.