Eleni Daniilidou (Greek: ????? ?a?????d??; [ele'ni ðani'iliðu]; born 19 September 1982) is a Greek tennis player from the island of Crete.
She is considered as one of the best Greek tennis players of the Open Era, winning five singles titles and three doubles titles on the WTA Tour.
In 2003, she reached the mixed-doubles final of the Australian Open, making her the first Greek player to have reached a Grand Slam final.
Her highest singles ranking is world No.
14, making her the only female tennis player from Greece to have reached the top 20.
No male tennis player had achieved this until Stefanos Tsitsipas reached the 15th place on August 13, 2018.
By beating Justine Henin in the first round of the 2005 Wimbledon Championships, she became the first player to defeat a reigning French Open champion in the first round of Wimbledon.