Jung Woong Na defeated Cheong Eui Kim 6-2 6-2 in the M15 Gimcheon 1 round of 32 on hard. The upset overturned the form book — Cheong Eui Kim came in leading the head-to-head 4–2, but Jung Woong Na had been the form player, winning 4 of their last 7 on hard. Jung Woong Na narrowed the head-to-head to 4–3.
| Date | Tournament | Round | Surface | Winner | Score |
|---|---|---|---|---|---|
| 2020-02-04 | M25 Nonthaburi 2 | Q16 | hard | Jung Woong Na | 5-7 6-1 10-7 |
| 2019-06-28 | M15 Anseong 1 | QF | clay | Cheong Eui Kim | 6-2 6-2 |
| 2019-06-08 | M15 Daegu 1 | SF | hard | Jung Woong Na | 6-2 6-1 |
| 2017-06-19 | Korea F4 | R16 | hard | Cheong Eui Kim | 4-6 6-2 6-1 |
| 2014-03-03 | China F1 | R32 | hard | Cheong Eui Kim | 7-6(4) 6-3 |
| 2013-06-24 | Korea F8 | QF | hard | Cheong Eui Kim | 6-3 6-2 |
Averages over each player's completed matches in the selected window (1 vs 12). ATP, WTA & Challenger.
Each player's serve crossed against the other's return, converted to expected hold of serve. Recent completed matches, ATP, WTA & Challenger. Small sample — read as indicative. About