Coach Andrea Stramaccioni gave Chatzigiovanis a debut as a late substitute in a 0–3 home defeat to Standard Liège in the UEFA Europa League.
[6] In October 2019, Chatzigiovanis signed a new three-year contract with Panathinaikos; it was reported that the player had insisted on a release clause being included.
[8] He crossed for Juan José Perea's goal against AEK Athens on 10 November 2019 that helped the team come back from a 2–0 deficit to win 3–2.
[13] On 2 February 2020, Chatzigiovanis scored in a 2–0 home win derby against reigning Super League champions PAOK, as he took advantage of some poor defending by Sverrir Ingi Ingason, and the Greek international forward clipped the ball delicately over Živko Živković, when clean through one-on-one with the visiting keeper.
[16] On 26 September 2021, he scored with a wonderful kick, his first goal of the season, after an assist from Carlitos, in a thriumphic 5–1 home win game against Volos.