Xanthi won its first Greek league match of the season, upsetting title hopeful Panathinaikos 2-1 on Sunday.
Pablo de Lucas opened the scoring for visiting Xanthi in the first half with a swerving free kick from the right.
Sebastian Leto equalized in the 62nd with a shot from just inside the area, but only four minutes later Theodoros Vassilakakis scored with a volley from 35 meters (yards) out that went over stranded Panathinaikos goalkeeper Luke Steele.
Defending champion Olympiakos beat Panionios 2-0 on Saturday and tops the league with Panathinaikos in second.
Also Sunday, Atromitos beat Veria 1-0 and PAOK prevailed over 10-man Iraklis by the same score.
Giannena vs. Levadiakos was postponed due to an earthquake which hit the city of Ioannina on Saturday night.