On 12 August 2018, he scored his first goal for the season, with a right footed shot from very close range to the top left corner, after Oussama Idrissi's assist in a 5–0 home win game against NAC Breda.
[4] On 7 November 2019, he lashed a thunderous effort high into the left corner, scoring his first goal in the UEFA Europa League in a hammering 5–0 away win against FC Astana.
[5] On 28 November 2019, Chatzidiakos suffered the dreaded anterior cruciate ligament injury while on UEFA Europa League game for AZ Alkmaar, medical tests have confirmed.
Subsequent medical tests this morning confirmed that the talented 22-year-old defender suffered the anterior cruciate ligament injury and will return to action after a period of at least six months.
As a result of his exceptional performances he was called in the Greece U-21 team from Antonis Nikopolidis for the 2019 UEFA European Under-21 Championship qualification match against San Marino and Czech Republic on 22 and 27 March 2018 respectively.