 Maroussi beat fellow Greek League club Aris, and the German League club Alba Berlin, in the EuroLeague 2009–10 season's Qualifying Round, to reach the regular season group stage of the competition.In the EuroLeague's Group C, they beat the Israeli League club Maccabi Tel Aviv at home, and reached the EuroLeague Top 16 Phase, where they beat fellow Greek club Panathinaikos and the Adriatic League club Partizan Belgrade, while playing home games at the Nikos Galis Olympic Indoor Hall.In the Greek Basket League 2009–10 season, Maroussi finished the regular season in third place.