On 25 March 2010 he scored his first goal for Ajax in a 6–0 win against opponent Go Ahead Eagles in the Dutch Cup. On 10 April 2010, Eriksen extended his contract with Ajax until the summer of 2014, stating ""I can still learn a lot here, I'm not finished yet and I hope I can mean a lot for the club."" On 6 May 2010, Eriksen played in the second match of the final of the 2009–10 Dutch Cup as Ajax beat Feyenoord 1–4, with 1–6 on aggregate. At the end of his first professional season at Ajax, Eriksen had played 21 competitive matches, scoring one goal, and had made his international debut for Denmark. For his second season in the first team of Ajax, Eriksen was given the number 8 shirt.