Seong Chan Hong defeated Sang Woo Noh 6-4 6-2 in the Korea F1 qualifying round on hard. The upset overturned the form book — Sang Woo Noh came in leading the head-to-head 1–0, but Seong Chan Hong had been the form player, winning 4 of their last 7 on hard. Seong Chan Hong claimed a first win over Sang Woo Noh in two meetings, levelling the head-to-head at 1–1.
Hong S. took it in straight sets.
Seong Chan Hong beat Sang Woo Noh 6-4 6-2. Umpiry, "Seong Chan Hong vs Sang Woo Noh — Korea F1 Qualifying Round", https://umpiry.com/match/2017-05-29/hong-vs-noh-korea-f1-qf?utm_source=cite (as of 29 May 2017).