A section of a stand at Eredivisie side NEC Nijmegen's stadium, the Goffertstadion, collapsed as Vitesse fans celebrated its side's 1-0 win, but there were no injuries.
Ajax has confirmed youth player Noah Gesser has been killed in a car accident at the age of 16.
Arjen Robben has decided to bring his playing career to an end just a year after announcing his return with boyhood club Groningen.
Ajax clinched its 35th league title earlier this month and decided to melt the trophy in a show of gratitude to its supporters.
Erik ten Hag has signed a new two-year contract at Ajax, effectively ending speculation linking him to the coaching vacancy at Tottenham Hotspur.
Ajax sporting director Marc Overmars said the club's chances of re-signing Barcelona star Luis Suarez are "quite small".