Although Georginio Wijnaldum felt the Netherlands' display in Poland was one of their best under Ronald de Boer, he believes work is needed.
Two goals in the space of seven minutes from Memphis Depay and Georginio Wijnaldum saw the Netherlands come from behind to defeat Poland.
A first win as coach of the Netherlands was satisfying for Frank de Boer.
The Netherlands could still qualify for the Nations League Finals after beating Bosnia-Herzegovina in Amsterdam on Sunday.
Barcelona have been strongly linked with Memphis Depay and the Dutchman seems to be encouraging speculation.
Donny van de Beek spoke about his start to life at Manchester United following the Netherlands' draw with Spain on Wednesday.
Georginio Wijnaldum captained the Netherlands against Spain but would have preferred regular skipper Virgil van Dijk to have been present.
Sergio Ramos earned his record-equalling 176th cap against the Netherlands, and Spain head coach Luis Enrique has talked up the achievement.
The Netherlands and Spain played out a 1-1 draw in Wednesday's friendly in Amsterdam.
After Tonny Vilhena left the Netherlands camp due to a positive coronavirus test, Ronald de Boer has called up Ryan Gravenberch.