(UPDATED 5 SEPTEMBER 2019)
- Broke into Top 20 and achieved career-high No. 19 on 2 April 2018. Passed Nishikori in ATP Rankings on 19 March 2018 to end Japanese player’s 7-year reign as No. 1 Asian. Peaked at No. 7 in juniors on 14 January 2013.
- Went 5-0 and defeated No. 1 seed Rublev twice, including in final, to capture 2017 Next Gen ATP Finals title. Went on to reach 11 QFs-or-betterin 2018, but still seeking 1st tour-level final of career.
- Earned biggest win of career over No. 4 A. Zverev and upset former champion Djokovic en route to 2018 Australian Open SF. Became 1st South Korean to reach Grand Slam QF and SF.
- Also became 1st South Korean to reach an ATP Masters 1000 QF, doing so back-to-back at Indian Wells and Miami in 2018.
- Won 70+ percent of matches on ATP Challenger Tour (84-27) and ITF Junior Circuit (84-32). Owns 9 Challenger titles, including 2019 Chengdu, CHN. Defeated Kyrgios and Coric en route to 2013 Wimbledon boys' singles final.