Ajax announced on Friday they had extended coach Ten Hag's contract until 2023
Ajax claimed their 35th Dutch league title on Sunday with a 4-0 victory over Emmen that gave the Amsterdam giants the Eredivisie crown with three games to spare.
Jurrien Timber, Sebastien Haller, Davy Klaassen and Devyne Rensch scored for Ajax in a game played in front of empty stands at the Johan Cruyff Arena due to anti-Covid measures.
The win gives Erik ten Hag's side an unassailable 14-point advantage over second-place PSV Eindhoven, who could only draw 2-2 against Heerenveen later on Sunday.
Ajax announced on Friday they had extended coach Ten Hag's contract until 2023, ending rumours he was headed to Borussia Dortmund in the Bundesliga or Tottenham in the Premier League.
"I am happy in Amsterdam and the management have assured me that the current squad will be retained and even strengthened in certain positions," said Ten Hag, who has coached Ajax since 2017.
Despite calls from the authorities to avoid gatherings, thousands of fans gathered around the stadium, according to Dutch news agency ANP.
Ajax completed the Dutch double two weeks after beating Vitesse Arnhem 2-1 in the Dutch Cup final.
No champion was crowned last season, which was halted in early March by the pandemic, with Ajax leading the table after having won the league in 2019.
They have continued their domestic dominance after selling several stars of the 2018-19 team which reached the Champions League semi-finals, including Matthijs de Ligt to Juventus and Frenkie de Jong to Barcelona.
Club president Edwin van der Sar said ahead of the win against Emmen the four-time European champions have "legitimate ambitions" in the Champions League over the next few seasons.
"Ten years ago, our goal was to return the club to the top echelons of European football. I think I can say that we have kept our word," he said.
"The next goal is to win a continental title and make Ajax a global brand. We are working hard towards that, not only on the sporting level but also on social networks and marketing."