Stefanos Tsitsipas (Greek: Στέφανος Τσιτσιπάς, pronounced ; born 12 August 1998) is a Greek professional tennis player. He is the youngest player ranked in the top 10 by the Association of Tennis Professionals (ATP) and has a career-high ranking of No. 6 in the world, making him the highest-ranked Greek player in history. He has won three ATP singles titles and reached seven finals.
Born into a tennis family where his mother was a professional on the Women's Tennis Association (WTA) tour and his father was trained as a tennis coach, Tsitsipas was introduced to the sport at age three and began taking lessons at age six. As a junior, he was ranked No. 1 in the world. He also became the third Greek player, and first Greek male in the Open Era, to win a junior Grand Slam title with a victory in the 2016 Wimbledon boys' doubles event.
Tsitsipas won his first ATP match in late 2017 and quickly ascended up the ATP rankings the following year. He reached three tour-level finals in 2018 and won his first title at the Stockholm Open. With his runner-up finish at the Canadian Open, he became the youngest player to defeat four top ten opponents in a single tournament. After culminating his season with an exhibition title at the Next Gen Finals, Tsitsipas continued to build on his success by reaching the semifinals at the 2019 Australian Open.