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.
We profile four young Chelsea players on loan at Vitesse, three of whom featured against Southampton.
Ronald Koeman admitted "it's never over in football" after Southampton beat Vitesse 3-0 in the Europa League.
Maarten Stekelenburg believes Southampton’s best years are ahead of them having joined the club on a season-long loan from Fulham.