Hong Chung defeated Min Hyoek Cho 6-1 6-1 in the Korea F4 qualifying round on hard. The upset overturned the form book — Min Hyoek Cho came in leading the head-to-head 3–2. That levelled the head-to-head at 3–3.
Chung H. took it in straight sets.
Hard: Hyoek Cho M. leads 3–2 · Clay: Chung H. leads 1–0
Hong Chung beat Min Hyoek Cho 6-1 6-1. Umpiry, "Hong Chung vs Min Hyoek Cho — Korea F4 Qualifying Round", https://umpiry.com/match/2017-06-19/cho-vs-chung-korea-f4-qf?utm_source=cite (as of 19 June 2017).