Chung Yun-seong
Introduction
Chung Yun-seong (Korean: 정윤성; born 27 March 1998) is a South Korean junior tennis player.
Chung has a career high ATP singles ranking of 562 achieved on 16 January 2017. He also has a career high ATP doubles ranking of 413 achieved on 9 January 2017. Chung has won one ITF doubles title.
On the junior tour, Chung has a career-high combined ranking of 3 achieved on 21 March 2016. Chung was a semifinalist at the 2016 Australian Open boys' singles event and the 2015 US Open boys' singles event where he fell to both eventual champions Oliver Anderson and Taylor Fritz, respectively. Chung was also a singles finalist at the Osaka Mayor's Cup in 2014.
He and Orlando Luz lost to Yishai Oliel of Israel and Patrik Rikl of the Czech Republic in the final of the 2016 French Open Boys' Doubles tournament, 6–3, 6–4.
Junior Grand Slam finals
Doubles: 1
| Outcome | Year | Championship | Surface | Partner | Opponent | Score |
|---|---|---|---|---|---|---|
| Runner-up | 2016 |  French Open |
Clay |  Orlando Luz |
 Yishai Oliel Patrik Rikl |
3–6, 4–6 |