Lasse Schone kicked off Der Klassiker in style with a stunning free kick just 53 seconds into Ajax's clash with Feyenoord.
The Danish midfielder had the chance with a long-range effort after Feyenoord committed an early foul.
And he crashed his shot into the net, giving Ajax a lead they would not relinquish for the remaining 89 minutes.
David Neres doubled the advantage in the first half, before Michiel Kramer scored a late consolation as Feyenoord went down 2-1.